# Calcium / Magnesium Relationship ?



## fish7days

What is the relationship between Ca and Mg in the planted aquarium and will the presence, or lack of, one influence the level of the other?

Thanks

André


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## Salt

While I am not an expert nor do I have matter-of-fact links to back any of this up, I believe that a calcium:magnesium ion ratio of between 3:1 and 4:1 (ca:mg) is optimal. Personally I use RO/DI water and dose a 4:1 ratio based on molecular weights.

I think this is something that is often overlooked, I see a lot of people say "I use Epsom Salts to raise GH," well that is only going to increase magnesium and it will be WAY high of a ratio to calcium.


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## Edward

Hi
I have done experiments with Ca and Mg levels and ratios. Generally plants don’t care about ratios as long as there are some levels present. Ca is immobile element and therefore must be present constantly.
Not the same can be said about mobile Mg. Mg can be dosed in very small quantities and still be sufficient. Additionally, higher levels of Mg harm some plant species, example is Rotala Wallichii.

Thank you
Edward


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## plantbrain

Edward, how high on the Mg?
I have some I saved from the SAE's, it's doing well, so of course I now want to torture it

Regards, 
Tom Barr


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## ranmasatome

im also interested to know how much and what kind of damage it does..?


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## NE

Edward, about what levels do you recomend for Ca and Mg as an approximate target.


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## Bert H

Having some issues with Mg, or lack thereof, I too would like to know what kind of damage you're talking about Edward in respect to wallichi. How does it manifest itself? Have you seen it in other plants as well?


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## plantbrain

Well, try it and see.

It's growing well for me, so I'll just add known amounts of Mg to the tank till I see a negative response.

Regards, 
Tom Barr


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## dennis

What about issues of Mg blocking Ca. I switched from Flourish to CSM+B several months ago and since then I have had many issues I contributed to trace defficiency. In the end I was dosing 6ml, 3x week, of the standard CSM+b solution to a 15 gallon, high light tank. Macros were dosed 4x week with 10mg/l NO3 and 1.5-2 mg/l PO4. Eco/onyx substrate, high fish load and press CO2 in the 25+ range. I also have a 10, similar setup and dosing but I dose 4-5ml CSM+B 3x week.
All my tanks run a Gh of 9+ and generally a kH of 3+
Even with all that trace I was seeing deficiencies of leaf curling, tip stunting and necrosis on the stems with plants, including Rotala vietnam (similar to wallachi in apperance and growth patterns) H. micranthemoides, Ludwigia arcuata, Hedoytis sp Rio, Mayaca fluviatalis, P stellata narrow leaf and even sever curling and white spots on new growth of Anubias nana and petite. A question posted here to APC lead to a response (by Phil Edwards) that the high Mg levels in CSM might be causeing a Ca blockage/deficiency. Not having any other trace to use, nor a local source for Flourish (*my favorite) I tried a quick fix of dosing 1 drop per gallon/per day of Kent Concentrated Liquid calcium. With in 3-4 days i was noticing signs of improvment. I did not change any other parameters during this time. I cut the liquid calcium and started adding 1/4tsp of Seachem Equilibrium. I now occaionally see small signs of stunting in my anubias, P stellata and HM but only on the occasional stem, not 3/4 of the bunch like before. All my other fine leaved plants succumed and were lost by this time. I attrubute most of my trace issues now with the high Mg, Ca and K that have to be in my tank by now. I need to get away from the CSM i think

Also, for some reason I can't seem to keep Nerite snails for more than a few weeks. Could it be related to the hardness ions?

What are ya'lls thoughts on this?


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## ranmasatome

Well Dennis,
i am using seachem flourish and dose 40ml per week (10ml each time..4 times per week) on top of this i dose the same amount of seachem iron.. and my plants still turn out like this with all this trace I see the same thing as you.. mainly being leaf curling, tip stunting and necrosis on certain stemsplants like didipls diandra. My Rotala vietnam was particularly BAD..but my other plants were pretty okay..even though if you look closely..they dont look like they are at tip top condition..the best that they can be.. 
so i added a bag of corals into my filter and after about a week.. boom... the vietnam came back to life.. and the DD started growning at an insane rate. Problem is i left the bag too long in the filter and now my kh is like 12!! and the plants are dying. So 2 weeks ago i removed the bag of corals and have now done 2 waterchanges since then..the plants are reverting back to their old self...and this really irritates me.. the tip of my ludwigia pantanal have colour but are small and scrony leaves.. so now maybe i'll go find some liquid calcium like you to dose..and see waht happens.. i will not change anything in the fert regime during this time..


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## Bert H

Dennis, I am curious if you have ever determined how much of your gh is from Ca vs Mg? In my case I have a gh of 11, and kept seeing curling stunting on and off on my A. reinickii. So I bought a Ca test kit and found most of my gh came from Ca. I started adding Mg and saw improvements, with still the ocasional stunting. I got some aromatica recently and am having a heck of a time with it - growing real slowly, older leaves getting pinholes and stems rotting. So I am in the process of gradually increasing the Mg to see if it helps. Do you know at what point (Ca/Mg ratio) is it you see inhibition?


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## dennis

Bert, in short, I don't know the answers to any of your questions. I can't find a Ca test locally that will work for freshwater so I have no idea of my hardness ratio. I don't think it is Mg deficieny as I though Mg would show up on older leaves. My issues all happen to new growth. Also, I know that my original fertalizing (with the CSM) added plenty of Mg but no Ca to speak of, hence my reasoning behind the Mg excess/Ca deficency. Adding Ca seems to have cleared up 90% of the problem. I have some Flourish on the way and will see how things look after using that for 2-3 weeks. I do notice the Gurus recommend Flourish or TMG but not CSM.


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## CrownMan

I am relatively new at this chemistry thing but I have an interest in this Ca/Mg relationship. According to my calculations, I need to be adding about 2.5 teaspoons of Epson salts to my 30 gallon tank each water change to get a 4:1 relationship of Ca to Mg.

Hopefully, my calculations are screwed up as that seems to be alot. Anyway, here's how I came to that conclusion. According to my city water company, I have 40 ppm of Ca in my tap water and my GH tests at 100ppm with 2 different testing kits. I downloaded a MgGH calculator program by Stuart Keeler and after plugging in that bit of info, it calculates I have 0 Mg in my tap water (which I believe according to the symptoms my plants are showing - old leaves have yellow/brown spots which develop to pinholes). According to the fertilator, I need to add 2.5 tsp of Epson salts to get about 10ppm of Mg to meet the 4:1 ratio.

I guess I have 2 questions. Is that correct, that I need to add that much? And if so, should I do it all at once or break it up over multiple days?

I am dosing EI, pressurized CO2 at 40ppm (KH of 4, Ph of 6.5), 4.5WPG for 6 Hours, 2.5WPG for 4 hours (2 lights, 2 timers), medium fish load, medium to heavily planted with Bacopa C., Rotala Rotundafolia, Hygrophila Difformis, E. Tenellus, Ludwigia Repens, Java Fern, Altenethera Reneicki.

Thanks,

Mike Herod


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## dennis

Bert H said:


> Dennis, I am curious if you have ever determined how much of your gh is from Ca vs Mg? In my case I have a gh of 11, and kept seeing curling stunting on and off on my A. reinickii. So I bought a Ca test kit and found most of my gh came from Ca. I started adding Mg and saw improvements, with still the ocasional stunting. I got some aromatica recently and am having a heck of a time with it - growing real slowly, older leaves getting pinholes and stems rotting. So I am in the process of gradually increasing the Mg to see if it helps. Do you know at what point (Ca/Mg ratio) is it you see inhibition?


Well I was finally to check my waer chemistry today. TDS from Hanna meter and Ca levels from Salifert test

Tank: Tap:
TDS 264 ppm TDS 96ppm
GH 12*= 213.6ppm GH 8*=142.4
Ca 150ppm Ca 120ppm
Mg 63ppm Mg 22ppm

That means that my tapwater has pretty good parameters but my tank water is out of wack due to, I assume, my heavy dosing of CSM and the use of and Onyx/Eco mixed substrate.

Also, can the tap measurments be correct? Is it possible to have a Gh higher than your TDS?


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## shalu

dennis said:


> Well I was finally to check my waer chemistry today. TDS from Hanna meter and Ca levels from Salifert test
> 
> Tank: Tap:
> TDS 264 ppm TDS 96ppm
> GH 12*= 213.6ppm GH 8*=142.4
> Ca 150ppm Ca 120ppm
> Mg 63ppm Mg 22ppm
> 
> That means that my tapwater has pretty good parameters but my tank water is out of wack due to, I assume, my heavy dosing of CSM and the use of and Onyx/Eco mixed substrate.
> 
> Also, can the tap measurments be correct? Is it possible to have a Gh higher than your TDS?


Your Ca and Mg numbers are stilll in CaCO3 equivalent numbers, the real ppm for Ca and Mg are:

Ca 60ppm 48ppm (divide your numbers by 2.5)
Mg 15ppm 5 ppm (divide your numbers by 4.1)

I guess it is possible for TDS and GH to mismatch to some degree. There are assumptions built into each that neither truely reflects the real ppm in your water. TDS measures electrical charges and assume that they are from a given composition of ions(depending on factory calibration fluid used, for example, NaCl, KCl, or some other salt mixture) and convert it into ppm. On the other hand. GH measures the total multivalent ions(mostly Ca++ and Mg++ typically) and assume that they are all from CaCO3 and converts it into CaCO3 ppm in most test kits. Still, it is a bit odd your tap TDS is so much lower. I did a simple calculation, assuming you only have GH ions in water and your TDS uses NaCl, it should actually give slightly higher reading than GH. Due to the electrical charge differences, TDS meter should see two NaCl molecules(molecular weight 56) for every CaCO3(molecular weight 100) molecule seen by the GH kit, unless this assumption of mine is wrong and they see it one for one.


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## dennis

So, in my tank I have 60:15 Ca:Mg, or 4:1. That is perfect now. Guess maybe that is why my stunting is 90% gone. this change probably happened in th elast 2 weeks since switching to Flourish and doing a few wc's with water that has a 9.6:1 ratio. That has probably helped balance things out a bit.

Now there is only one problem. Silly me, I just went and dosed 35ppm Ca. I added 20 ml of Kent's Liquid Calcium. I figured I needed 100ppm of Ca, based on my previous post of 150ppm Ca and 63ppm Mg, to bring my ratio up to the correct amount. I figured adding about 1/3 this week would be a good start in the right direction.

Nuts! Think that will hurt anything?

Oh, and BTW....in my 12 degree hard water, I am growing Rotala sp, formerly known as Ammania Bonsai, Downoi, P. stellata and Ludwidia Cuba with beautiful success. The plants I was having stunting issues with before were P stellata, Anubias nana, H. micranthemoides and Mayaca fluvitalis.

guess I won't have calcium issues for a few weeks huh


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## shalu

Keep in mind that our tests have limited resolution and your tap water only has 5ppm Mg, so it could have been less. I bet the problem was TOO LITTLE Mg in the beginning. Now that you have about 15ppm Mg, things look better. I had similar stunting issues, adding Mg via epsom salt helped a lot.


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## dennis

I would be inclined to agree with your Shalu except for 2 things. First, I don't know what my parameters were a month or 2 ago whe this issue was real bad, but I do know I was dosing heavily with CSM+B, a product that contains lots of Mg but almost no Ca. I was not adding Ca or Mg from any other source except water changes. Secondly, the issue I had with m y plants was easy to see in the Anubias leaves. New growth only was affected and the problems were litght spots, curling and holes in the leaves. Mg is a mobile nutrient, meaning that plants will take it from old growth to feed new growth when there is a deficiency No plants in my tanks exhibited issues with old growth.


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## shalu

I know people say Mg affects mostly old growth, but my problem was mainly with new growth, and adding epsom salt definately helped a lot, especially with alternanthera reneckii stunting problem. I think mg in CSM will hardly make any dent in terms of ppm, did you estimate how much it was really adding in terms of ppm in the tank? Ok, I did a rough estimate, typically it will be 1ppm per week of dosage, 2ppm Mg per week from very heavy dose of CSM.


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## plantbrain

Mg is more common for issues, many suggested it was K+, but CO2 and Mg will influence that more than Ca which tends to rarely an issue but an oft loved excuse for poor growth.

High levels of NH4+ and Mg++ will block K+ far more than K+ ever will.
And there is research to support that.

So do not go nuts with Mg.
You just need a little bit and the ratio itself is not going to cause much issue if the Ca is high. 10-20ppm is more than enough. 

Regards, 
Tom Barr


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## dennis

So I now, theoretically, have 95ppm Ca and 15ppm Mg. 

What do you recommend I do now and in the future? If my tap readings are correct, I will want to start adding Mg eventually correct, but not for a while. I assume that with those numbers I don't need to worry about K. I add 25+ppm K each week with with my Macro additions.

Bahhhh, why does this confuse me so sometimes.


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## Edward

Hi All

The Rotala wallichii been growing well at 20 ppm Ca and 2 ppm Mg. However, it stops growing when Mg changes to 10 ppm. When conditions change back to 2 ppm Mg the plant starts growing again. Please see the picture.










This test I have repeated several times. Please take in consideration that the Mg is from MgSO4, not MgCO3. The Ca is from CaSO4 and CaCl2, not CaCO3 nor CaNO3.

Thank you
Edward


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## dennis

Thats interesting that you show that for an example. I have Mayaca fluvitalis, a plant with very similar leaf and growth patterns to Rotala wallachi, that exhibited these same growth patterns when I was having all my issues. the growth has returned to normal since switching to Flourish, adding Ca and many water changes. Basically increasing the Ca and decreasing the Mg concentrations in the tank water.

Question is: are the improvments a result of higher Ca, lower Mg or both?


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## plantbrain

Edward said:


> Hi All
> 
> The Rotala wallichii been growing well at 20 ppm Ca and 2 ppm Mg. However, it stops growing when Mg changes to 10 ppm. When conditions change back to 2 ppm Mg the plant starts growing again.
> This test I have repeated several times. Please take in consideration that the Mg is from MgSO4, not MgCO3. The Ca is from CaSO4 and CaCl2, not CaCO3 nor CaNO3.
> 
> Thank you
> Edward


I'll give this a whirl.
I like the Rotala and it does grow back fast when happy.
What might be interesting is focusing on the KH vs Mg.

I know many folks that have rather high GH's, many from dosing SeaChem Eq and in a number of cases they have Mg over 10ppm but an associated higher level of Ca as well.

Ca/K/Mg/NH4 blocking all appears to need to be much higher concentrations typically found in pore water to start to get blocking. But species to species difference may play a larger role.

I have found the Luwigia cuba to stunt much like the R wallichii in the hard KH/GH's, but teasing apart which is causing what requires more grow out and then changes to the Mg, KH and Ca levels.

In general, if there is a GH issue, lower Mg is typically the reason if the GH is already high, it's virtually unheard of to find high Mg and low or limiting Ca levels if the Gh is 3-5 degrees or high.

Many folks have high GH's and does well with Rotalas and Ludwigia cuba.
It might be evidence of a ratio being important even at low concentrations.

Regards, 
Tom Barr


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## dennis

plantbrain said:


> In general, if there is a GH issue, lower Mg is typically the reason if the GH is already high, it's virtually unheard of to find high Mg and low or limiting Ca levels if the Gh is 3-5 degrees or high.


This may be true but it _could_ be a dangerous way of thinking. This statment considers natural water sources. Our tanks have the potential to be anything but natural. In my case, I was doseing for several months a trace that contains higher Mg but no Ca. I was dosing no other source of Ca, except via water changes.

Here is where i assume there is a catch. At the time of my tank issues, my water supply changed, as it often does in the dry summer months when the town changes to a different source. My tap kH goes from 4-5 to 0 and the Gh changes from 8-9 to 12+. Why, living in the New England area of the US, would I have a 0kH from a natural source? I wish I knew what my Ca/Mg was form this time but I had no way to test then. If 0kH is possible why not high Mg, low Ca? That is not sarcasm, that is a seroius question. Could the water company be somehow filtering/treating the tap and affect these conditions? Contacting my local water company is an exercise in futility.......

For probably 3 months in the summer I was dealing with the different water parameters and towards the end, these difficiencies. Also, I switched to CSM in April, that is 5 months for the MG to build up in relation to the Ca. This tank gets a 40% wc weekly. Just my observations.



> Many folks have high GH's and does well with Rotalas and Ludwigia cuba.[/quote
> 
> I have not really had issues with rotalas but my L. Cuba was stunting heavily mid-late summer. After my water supply went back to normal and I started adding 1/8tsp Seachem Equilibrium at wc, it has been growing gang busters. Probably for the last month or so.
> 
> 
> 
> 
> It might be evidence of a ratio being important even at low concentrations.
> 
> 
> 
> I thought you always say ratio does not really matter as long as the Gh is over 3-4  Just yankin your chain!
Click to expand...


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## Edward

Hi Dennis
let's not confuse Total Dissolved Solids TDS with concentration in ppm.

A TDS meter measures electrical conductivity or resistance of a solution, whichever you understand better.

1 / resistance = conductivity
1 / conductivity = resistance

Pure water = low conductivity and high resistance.
Impure water = high conductivity and low resistance

Resistance in Ohm
Conductivity in Siemens

We are still talking electricity here. So why is your tester calibrated in ppm? This is where the confusion comes from. TDS testers calibrated in ppm instead of Siemens. Someone had this idea to use NaCl or kitchen salt solution to display in ppm. It may work better for some applications but not for aquariums and water works.

How to get out of this mess? We can get approximate result back to conductivity value:
uS = 2 x ppm
ppm = uS / 2

MicroSiemens [uS] is the right way to talk about water TDS, however, every element conducts electricity in a different rate so there is no way to tell what elements are in the solution.

Edward


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## plantbrain

dennis said:


> This may be true but it _could_ be a dangerous way of thinking. This statment considers natural water sources. After my water supply went back to normal and I started adding 1/8tsp Seachem Equilibrium at wc, it has been growing gang busters. Probably for the last month or so.
> 
> I thought you always say ratio does not really matter as long as the Gh is over 3-4  Just yankin your chain!


They don't, but your new routine adding a little bit of SeaChem Eq each week will address the issue(which is Mg limitation), we found this out about 10 years ago in the Bay area using this product.

Many thought it is was all the K+, which was all the rage back then.
Some thought it was the Ca, Steve Dixon wondered if it was the Mg. He's alos the guy that found out I had such high PO4.

He had so many things right on looking back, too bad he's not active any longer.

I'm about ready to torture some wallichii also. Bring on the salts!

Regards, 
Tom Barr


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## jerseyjay

Dennis, 

I just read this post and noticed that you were having some issues with GH: Ca / Mg ratio. Seemed like Seachem Equilibrium helped, no ?

Why going with Greg's GH Booster now ?


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## dennis

I am not exactly sure what my issues are but I do belive it is Ca or Mg deficiency. I will be testing the addition of each nutrient seperately before I try the Greg's/Tom's booster Equilibrium seemed to help before although I have no difinitive proof. I would like more this time. 

As for why the change; I was ordering from Greg anyway, its cheaper and the Equlibrium is hard as a rock and doesn't seem to dissolve that well. I don't entirely trust any powdered material that I can't stir up as I don't know how well it is mixed or why it is hard. I literally have to scrap off small bits with a metal spoon to use what I have. I also know Equilibrium has lots of K and I am hoping the Booster has less, although I have not done the math yet to figure it out. Thats a project for tomorrow when I am less sleepy.


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## plantbrain

Most salts will absorb water and become rock hard rapidly, that's why they add rice to absorb water vapor to salt shakers.

I'll do some measurements for the GH booster, dang, i hate it when my name gets attached to something

It's Greg's Creation inferred from something I wrote at one point.
It should have the same effect as SeaChem Eq if used the same although it has less K and more Mg if he used something I said.

You have weird tap, one of the few that has high Mg.
This is a good thing though, you can see what impact high Mg has on plants.

Edward's example did not look good
But you never know.

I've had all sorts of Ca levels and K levels etc, I suppose I can really max the Mg out, I've been meaning to anyway. 
Done most of the others.

I've never found any evidence of a ratio based issue though with Ca/Mg/K to date in any research. As long as they are non limiting and not extremely high, they do not impact crop production. I typically look at rice studies since they are the huge ag crop that is also an aquatic plant.

Regards, 
Tom Barr


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## dennis

Searching for research about rice, thats a real good idea!

The photo Edward posted looks like the issue I used to have with Mayaca fluvitalis and others. Now I have the same stunting issue with Rotala najanshen, Posogtemon stellata and occasionally with Rotala green and Hemianthus micranthemoides. The new leaves of Anubias barteri ver nana Petite exhibit some holes, occasional yellow dots, etc and new growth on Pogostemon helferi has some pure white areas. I would be inclined to believe you that it is low Mg (you should certainly know better than me) but for the fact that th eissue is strictly with new growth. Ca is immobilbe while Mg is mobile, correct? If it was Mg shouldn't the issue be with old growth?

50 gallon tank,1.4wpg-2hrs, 3.64wpg-5hrs, 1.4wpg-4hrs. NO3, PO4 and traces are all dosed in excess 10:.5ppm NO3O4-4xweek and moderately high fish load. Traces= 45ml Flourish week+15ml Flourish Fe. CO2 added via diffuser until fish stressed.

The way I read it there are 3 possible causes for this issue:
-high or low Mg
-Low Ca
-low K

To be honest I am not certain my water test reading were accurate last time; seems there was some confussion with the TDS, Ca reading, CO3 equivilant, etc.

I am trying to do it right this time. I have ordered Lamotte Ca and kH/Alk test kits. I will callibrate my current Aquarium Pharmacuticals Gh and kH test kits (see see post 5 here http://www.aquaticplantcentral.com/forumapc/showthread.php?t=10305 )

I need to do a wc and basic maintainance tomorrow. Before the wc I will take several samples in cleaned, 12ml test tubes and cab with saranwrap, parafin sealing film then a cork. I will take several after the wc also as maybe the stunting is occuring early in the week and maybe later in the week? (I though it is possible that the wc is either adding enough of a nutrient fo rgrowth early in the week but that become deficient later; or, the wc is removing something that my pH6.4-6.5 is dissolving from the substrate) I have planty of tubes so its no biggie.

I will test these samples once I get my kits and report back.

In the mean time, what to do? I want to start adding CaCl2 now, say 15ppm? (that would be about the equivilant of raising the GH 2 with Booster/Eq) after the wc as I don't like the poor growth.

Could it be low K? I add ~26ppm weekly through my KNO3/KH2PO4 dosing. Unless it is in my tap I would not get it any other way.

Oh yeah.. I can grow Tonina, Ludwigia cuba, P helferi, and HC just gang busters. 

Any thoughs on my thoughts are appreciated, from anyone.

(I have a Soils class with a lab this semester..wonder if they have any fun equipment?)


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## NE

> I would be inclined to believe you that it is low Mg


I guess this is not that important, but i thing Edward is having problems when the Mg levels gets to high.


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## dennis

NE,

Reciently, in other threads Tom has posted that my issues are probably low Mg. What you quoted me as saying is part of a statement where I was saying that while I know I should believe someone with as much experience as Tom, for some reason low Mg does not make sense to me for this. I agree that high Mgandn low Ca could be an issues. Now I need to test that

Sorry for any confusion.


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## NE

OK, sorry i thought it referred to Edwards post.

I'm very interested in this as well.
I have had major problems with stunting, now i add Mg and Ca and it seems better but i dont know what levels i should have as target to get the best growth.

It's going to be very interesting to hear about your conclusions.


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## JLudwig

Hi gang... there are two plants giving me similar issues, L. "Pantanal" and sometimes R. macrandra "green". The rotala surpises me a bit since it used to grow really well for me. What will happen is that occassionally, early week after a WC it would stunt, then later in the week would have nice growing shoot sent out already, but not as prounced as what Edward posted. I've tried a few things and seem to have it under control, at least with the rotala. I basically starting going to 1/2 RO 1/2 tap, and switched back to entirely TMG as a trace, 2ml/day per 10 gallons, 6 days a week. Rotala is now fine - now I'm working on the Pantanal.

I tried elevating both Mg and Ca in the proper ratios, that didn't help, also adding more Mg didn't help. So now I'm trying two weeks of elevated calcium, if I forget to update the thread please PM me and I'll post results. Everything else in the tank is growing fine so its a matter of getting some of these fussier plants to stay happy.

Jeff


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## RuslanJamil

Would it make any difference if the Mg is in chelated form? I've noticed that some hydroponic growers use the chelated form even though MgSO4 is much cheaper...


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## plantbrain

There's no need to chelate Mg, but Mn is another matter.
Typically in traces, Mn as well as Zn, Cu, are chelated, EDTA.

Regards, 
Tom Barr


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## dennis

OK chemistry people:

I just got a LaMotte Ca test today and 2 runnign 2 tests I get the same answer of 95ppm Ca, read as ppm Calcium Hardness as CaCO3.

In the following equation used to find the ppm of Mg, does the Ca in ppm number need to be converted from my reading of 95ppm as CaCO3? If so, I would divide by 7.143?

GH in ppm - (2.5*Ca in ppm)
--------------------------- = Mg in ppm
4.1

Any help is appreciated!


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## plantbrain

JLudwig said:


> Hi gang... there are two plants giving me similar issues, L. "Pantanal" and sometimes R. macrandra "green". The rotala surpises me a bit since it used to grow really well for me. What will happen is that occassionally, early week after a WC it would stunt, then later in the week would have nice growing shoot sent out already, but not as prounced as what Edward posted. I've tried a few things and seem to have it under control, at least with the rotala. I basically starting going to 1/2 RO 1/2 tap, and switched back to entirely TMG as a trace, 2ml/day per 10 gallons, 6 days a week. Rotala is now fine - now I'm working on the Pantanal.
> 
> I tried elevating both Mg and Ca in the proper ratios, that didn't help, also adding more Mg didn't help. So now I'm trying two weeks of elevated calcium, if I forget to update the thread please PM me and I'll post results. Everything else in the tank is growing fine so its a matter of getting some of these fussier plants to stay happy.
> 
> Jeff


Probably CO2 then.

Rotala's love it when it's high, a little drop off and you'll get stunting.

I think that is the main issue with many folk's stunting issues and certain species issues.

They see one thing and incorrectly attribute it to Mg or Ca.
I'll suggest adding most every nutrient to excess, that is relatuively easy to do.

From there all you do is tweak CO2.
This is the best method to get good growth for folks.

We can add known amounts of Ca/Mg/NO3/K/PO4/etc, then adding CO2 is all that is left.

We can gauge the max amounts that might be needed by other folk's parameters for the same plants.

From there, if those match up, CO2 is the only thing left.

I see too much confidence in folk's reports of CO2 levels and reports of very wide ranges of CO2 ppm readings for it NOT to be a huge issue.

I'd say many/most of the Ca/Mg issues are CO2 related.

Regards, 
Tom Barr


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## dennis

So does shutting of CO2 at night affect plants? Mine comes on with the first bank of lights, (I get about a .3-.4pH shift between lights off and lights on) and CO2 is added 'til the fish HATE me!

I just finished testing my water parameters with Lamotte and calibrated test kits:

GH-
Tank-7.5 (134ppm)
Tap- 6(107ppm)

Ca as CaCO3-
Tank- 95ppm
Tap-80ppm
alternately Ca as elemental
Tank-38ppm
Tap-32ppm

So Mg elemental:
Tank-9.5ppm
Tap-6.6ppm

Yet still I get stunting of Rotala green, R. najanshen, Pogostemon stellata and Anubias nana Petite but not A.coffeefolia or A. nana.

Of course, adding CO2 tillI get fish stress may not mean I have high CO2 but low O2. Calibrated monitor, no electrical interference, says 6.5 with a positive kH of 5. Only way my CO2 could be off is if my pH is affected by PO4 or some organics but I have a fairly clean tank and little wood(manzanita). As for O2, I have a good amount of surface movement and good tank circulation. There is no fish stress in the morning, only during mid photoperiod once the CO2 has been on for some time and the pH has dropped to 6.6-6.5.

So know whats wrong?

kH 5


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## plantbrain

dennis said:


> OK chemistry people:
> 
> I just got a LaMotte Ca test today and 2 runnign 2 tests I get the same answer of 95ppm Ca, read as ppm Calcium Hardness as CaCO3.
> 
> In the following equation used to find the ppm of Mg, does the Ca in ppm number need to be converted from my reading of 95ppm as CaCO3? If so, I would divide by 7.143?
> 
> GH in ppm - (2.5*Ca in ppm)
> --------------------------- = Mg in ppm
> 4.1
> 
> Any help is appreciated!


Your Ca is 95ppm x mol CaCO3/ mol Ca = 40.08+12+3x16/40.08 = 2.5
95/2.5= 38ppm Ca++

The above equation off hand appears right.

Say the GH (total hardness as CaCO3) is 120ppm.
120-95 = 25ppm Mg as CaCO3 equivalents.
25/4.1= ~6ppm Mg.

I'd not bother with this, knowing the difference between a few ppm in a ratio is not going to do much for you unless you desire to add very small, potentially limiting amounts.

Nothing I've found suggest a ratio of Ca/Mg does much, the amount of error in our testing and habits plays a much more significant role I would suggest.

Add a little of both Ca/Mg to your tank each week beyond the amount of plant growth requirements, say 10ppm of Ca++, and perhaps 4ppm of so of Mg++ and you are set. That's in addition to the Mg/Ca in your tap water, other sources.

Regards, 
Tom Barr

PS- 
I recently bumped my Mg up with Rotala wallichii, unlike Edward's photo's, it did not stunt. I am using soft water(KH = 2) and low GH's.

5.4 grams in 1 teaspoon of MgSO4*7H2O.
9.9% of it is Mg.
So per gram of Epsom salt added to one liter: 9.9/100= 99 ppm or mg/L.
So per gram added to a 75 liter(20 gal tank) 99ppm/75= 1.32 ppm Mg++.

5.4 x 1.32 ppm= ~7ppm of Mg.

I added 1.5 teaspoons, a fair amount of Mg to such a small tank. 
10.5ppm and that does not include the fraction for the tap.
Generally 1/4 to 1/2 teaspoon per week will address any Mg issue.
But those with higher GH's, likely can use more if they want without issue.

I have not done enough with Mg to say much still. 
I only did the Rolata test once. I waited for 3 days after. 
So who knows just yet.

Still, adding the rec's I suggest are fairly light, not excessive, if you apply the EI notion to 2x the weekly build up if no Mg is used, then the amounts end up in the 2-6ppm range generally.

Folks have been using Mg in PMDD and with other mixes for a long time.
I tend to suggest a few degrees of GH for soft water, about 3-4 at least using SeaChem EQ or the Gh booster, folks with harder GH waters may need some Mg or Ca to balance things out so neither is limiting.

I think you can approach it that way, using just GH and adding a bit more with a balanced product or................you can analyze GH individually into the Ca and Mg sereprate nutrients.

I'd stick with one method though, that will simply things.
At the end of the day, I do not think you will see marked differences with either method.

Both can supply the required amounts of Mg and Ca.
One test more, the other uses a GH kit or none at all.

Simply because you do not test, does not mean you need to know what the ppm of Ca/Mg, only that you have enough to prevent limiting conditions.
That's the real issue for 99% of aquarist, not confusing themselves with test kits/methods.

Why test unless there is a problem?
How do you avoid such problems to begin with?

Pretty straight forward.
If you suspect K+ is limiting, then add more K+ and see.
You do not need to test the K+, you can if you want, but you do not need to do so to know the K+ is limiting or in excess. Simple calculators will tell you that.

Regards, 
Tom Barr


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## JLudwig

plantbrain said:


> I see too much confidence in folk's reports of CO2 levels and reports of very wide ranges of CO2 ppm readings for it NOT to be a huge issue.


Well I do think I can cross that one off, as I use a calibrated pinpoint probe, and don't measure KH. A sample of my tank water goes up 0.8-1.0 pH points with a few hours of vigorous aeration with an airpump, Ive found that to work pretty well. Other than upping the dose of calcium, I've backed off on my trace a bit, maybe its not a deficiency but a toxicity issue, whatever the problem it's (a) hard to reproduce and (b) only affects the fussiest of plants. Mg/Ca ratio is a good scapegoat, it will one day mysteriously get better, I'm sure of that. A "heisen-bug" if you will. And the whole exercise is a bit pathological as I would easily sub in one of the 300 other plants I can grow well 

Jeff


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## dennis

Tom,

That's the first time I have ever seen you do math! Not that you don't do math, just never seen you type it all out. Now I feel special 

Jeff, you pring up a good point regarding using a pH shift rather than kH to measure CO2. In my case, fully settled tank water is 7.0 but by 6.5 fish are gasping. This stress does not happen right before lights, and CO2, come on, as I would expect but rather midday once the CO2 has been cranking for a couple hours. The increased lighting period I run midday creates some extra O2, visable as heavy pearling, but this obvious sign of O2 saturation does nothing to alleviate fish stress. I can only assume from this thathigh CO2 levels are to blame. However, this does not explain the only .4-.5 pH drop the tank can handle.

Incidently I use the intank diffuser method with lots of mist.

I think I may have to do some mucking with surface movement but anymore turbulance and I will get whitecaps!

Tom,

Thanks for all your help with this. It seems that my water parameters are definately within the limits with nothing excessivly low or high, much as you assumed it would be. I may try just adding some GH Booster or Equilibrium but I really wanted to pinpoint this, if for no other reason than personal satisfaction!

Jeff, I orignally though via other's suggestions that possibly I had a high Mg affecting Ca, as unlikely as that was. Plus, the fact that only new growth and not old growth was affected pointed to immobile nutrient deficiency. However, providing I have calibrated my GH test correctly and done all the math correctly, my Ca and Mg are definately in good shape.

So, what are our other options....
a)faulty test readings
b)CO2 fluctuations/limitations Do you turn off the CO2 at night?
c)Toxicity of some trace element 
d)Low K
e)Low some other trace

Any other possibilities?

Oh, and


> And the whole exercise is a bit pathological as I would easily sub in one of the 300 other plants I can grow well :smile:


But that would mean admitting defeat!


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## plantbrain

JLudwig said:


> Well I do think I can cross that one off, as I use a calibrated pinpoint probe, and don't measure KH. A sample of my tank water goes up 0.8-1.0 pH points with a few hours of vigorous aeration with an airpump, Ive found that to work pretty well. Other than upping the dose of calcium, I've backed off on my trace a bit, maybe its not a deficiency but a toxicity issue, whatever the problem it's (a) hard to reproduce and (b) only affects the fussiest of plants. Mg/Ca ratio is a good scapegoat, it will one day mysteriously get better, I'm sure of that. A "heisen-bug" if you will. And the whole exercise is a bit pathological as I would easily sub in one of the 300 other plants I can grow well
> 
> Jeff


One measurement or two in time means little, you need to keep track of the CO2 over the course of the treatment. 
At least one full day of observation and then thereafter am/pm or if anything is funny looking.

It's nothing like NO3 at 20ppm.
In 30 minutes a tank's CO2 can drop fast.
Many things influence CO2.

The more I know, the more I doubt.
Uncertainty is high is all.
I've seen evidences of CO2 ppm changes throughout the day on many tanks.
I'm very leery of CO2. 
I play with that much more than any single nutrient.

I can help with the toxicity issue.

I added 200mls to a 20 gallon tank of Flourish, not 20, but 200mls.
The water was very dark and stayed that way over the 3 day peroid.

No stunting, not shrimp issues, nothing relatable to toxicity was ever observed. I used TMG to dose to 2ppm of Fe a decade ago, I had very good plant growth.

Regards, 
Tom Barr


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## plantbrain

dennis said:


> Tom,
> 
> That's the first time I have ever seen you do math! Not that you don't do math, just never seen you type it all out. Now I feel special


Don't.
I scare folks with talk, add math and they really cringe.
I've posted plenty in the past that details out Chemistry.
There are links all over going pretty far back.



> However, this does not explain the only .4-.5 pH drop the tank can handle.


Well, that right there explains a lot of your tank's issues, more than the Ca/Mg thing.

You can change this by adding more surface movement, a slight rippling is good, flake food should move around the surface but not be torrented under the water.



> I think I may have to do some mucking with surface movement but anymore turbulance and I will get whitecaps!


Then white caps it is. 
But........the testing method for pH............what are you using? Get a pH pen or monitor if you do not have one.
Most everyone can knock it down a full pH unit without issue.



> I may try just adding some GH Booster or Equilibrium but I really wanted to pinpoint this, if for no other reason than personal satisfaction!


Well, careful of what you wanna know there.



> Plus, the fact that only new growth and not old growth was affected pointed to immobile nutrient deficiency.


Low CO2 suddenly also causes the same expression, stunted smaller growth of the vegetative tips, is CO2 a mobile or non moblie nutrients?
This is a trick question.



> a)faulty test readings
> b)CO2 fluctuations/limitations Do you turn off the CO2 at night?


You can easily rule out the K+ if you use KNO3.
Traces: see previous post.
They are traces, while needed, they have a wide range, and the expression is very difficult to prove in isolated studies of what the stunting might look like. Measuring tiny tiny amounts is very difficult except in highly controlled studies.
Toxicity has never been show in aquariums with Flourish or TMG to my knowledge. I certainly have been unable to show it when dosing even 10x the normal high dosing amounts.

So focus more on a and b. That and the pH drop says a lot.
Don't worry, even the best get nailed with CO2.

BTW: here's why the K from KNO3 is unlikely to be an issue in terms of limitation:

http://www.aquariacentral.com/forums/showthread.php?t=21033

One poster had a common error, but it was caught and corrected.
Unless you have nearly 75% of the N coming from some other source, such as fish load or tap, it's very unlikely you need extra K from K2SO4.

Steve Dixton postulated both the K was enough from KNO3 alone and that adding Mg was more critical than we thought.

He said that to me back in 1997.

Regards, 
Tom Barr


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## JLudwig

dennis said:


> a)faulty test readings
> b)CO2 fluctuations/limitations Do you turn off the CO2 at night?
> c)Toxicity of some trace element
> d)Low K
> e)Low some other trace


Dennis I use a JBJ solenoid so its only 12 hrs of CO2 a day. I could run the CO2 all night and see what happens, when I had no trouble with the rotalas (I've got the plantfinder picture of the same plant giving me guff right now, go figure  ), I was on a 24 hour cycle. Hmmm....

With respect to your problem I would get to the bottom of that pH issue ASAP. Something is wrong with your pH measurement, it sounds like the gain on your instrument might be out of whack. When was the last night you bought a new probe?

Low K? Don't know, K is immobile IIRC so not sure that would cause stunting in new growth.

Jeff


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## dennis

JLudwig said:


> Dennis I use a JBJ solenoid so its only 12 hrs of CO2 a day. I could run the CO2 all night and see what happens, when I had no trouble with the rotalas (I've got the plantfinder picture of the same plant giving me guff right now, go figure  ), I was on a 24 hour cycle. Hmmm....
> 
> With respect to your problem I would get to the bottom of that pH issue ASAP. Something is wrong with your pH measurement, it sounds like the gain on your instrument might be out of whack. When was the last night you bought a new probe?
> 
> Low K? Don't know, K is immobile IIRC so not sure that would cause stunting in new growth.
> 
> Jeff


Jeff,

Yes, the pH/CO2 issue has become my new priority. I tried cranking the CO2 a bit more by lowering the set point of my monitor down a little. I also increased the surface flow a little and added a PC fan to my hood to try and promote air movement over the water's surface, there by increasing O2 and reducing fish stress from adding more CO2. All the fish were alive when I got home tonight but that does not mean they were not stressed while I was gone. Lights have been off for about 2 hours and pH is 6.6.

I have not replaced the probe in about 1.5 years (technically never replaced the probe as I bought the unit new then). I have observed the readings with lights on, lights off, in fact with all power to the aquarium off save for the controller itself. Never a change in readings and I have done this several times, once very reciently. The probe calibrates very easily, never straying more than .1 in a month and always tests right to 7(or 6.9 depending on how long it was since last calibrated) when checked with a new sachet of pH 7.0 calibration solution. I have checked this and checked this and checked this and it does not seem as though the probe is bad. I even once tried sealing the probe up in a sachet for several hours to see if it wandered then...nothing. I suppose I could get a new probe but at $50... I may try running without the controller and just go by bubbles count and observation.....

Any recommendations for a starting bubble count on a 50 gallon, lots of surface movement and in tank ceramic diffuser?

From my reading K is mobile so low K would not affect new growth; however, I have also read that low K can reduce uptake of Ca, not block but reduce through slowed growth. K is also major in root development and stomata regulation (I think). I have noticed a signifigant decrease in root development in most of my plants over the last couple months, especially Bylxa japonica, which was usually a strong rooter, HC, aswell as Lobelia and stems like L cuba and P stellata, which used to produce extensive roots. There are no "aerial" roots comming form the Rotala's. My tank gets 4x week dose of 10:6:.5 NKP via GW ferts, or 40ppm NO3, 24ppm K and 2ppm PO4. I know I am dosing that so it doesn't seem like low K is an issue, nor low Ca, nor low Mg, or high Mg..... Also, the lowered rooting could be that the tank is more mature now and the plants not needing to resort to substrate nutrients due to plenty of water column nutrients. I just don't know.

Must be a CO2 thing


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## dennis

Well,

I ate some crow Thursday, boy was it good. I saw the sticky in the equipment forum about testing pH probes. Turns out mine must be bad. Only hit about 8.5 in the Windex, soaking an alcohol and then rinsing/recalibrating only made it worse. It tested immediatly to 7.o in the bufer solution though.

Fool me once, idiot

So I increased surface movement as much as possibe, I'll not get more without using an extra powerhead but Eheim 2217 on a 50gallon should be sufficient! I also added a PC fan blowign across the surface of the water thinking I may not have been gettign good air diffusion in my canopy. Lastly I cranked the CO2 even more.


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## zenfish

Very interesting thread to say the least.Andif I may interject a few photos of what is going on in my tank..this is the link HTTP://community.webtv.net/victory_life/75gallonIT is to highlight the problem I am having with a few plants,but mostly a sword.the leafs are coming up quick,but they are coming up white.
It seems to possibly be a mag/cal deficit I a thinking or maybe even iron.
the tank has been set-up for about 2 months.and here was my last weeks dosage.
feb 13th.0.58ppm of kno3 as potassium nitrate.
14th.same kno3 and 2 ml. flourish trace
15th.same dosage of both
16th.same dosage..
my water is very hard out of the tap,well water in N.E. oklahoma..s I was adding ro water to cut it..well I may of cut it too much although would still ge moderate readings on my dip-stick..I know probaly not he best way to test,but no pet stores close...
anyway,,yesterday the 18th.. did a 20 gallon water-change and am going to stay away from the RO water for a few weeks and see what happens..
today I added for ferts.feb 18th.
1/2 tsp. of potassium nitrate
15ml. of flourish
10 drops of fleet..(thats a whole lot of fun buying at the store)..LOL
and 1/4 tsp. of epsom salt.
I do not currently have any iron supplement to dose.although I did put aroot-tab from aquarium plants.com at the base of the sword as well as afew crypts.and also have laterite mixed into a gravel base.
no major algae problems to speak of,although have some green spot.
the last dosages I did am going to stick with for a few weeks and see what happens.although any advice would be very helpful...also,only o my hygro poly and hygro "sunset" getting the small holes on the old growth leaves...
If anyting I hope these pics help others to see what some nutrient deficencys look like..and to hopefully get me some answers....
Thanks all.
peace and plenty,
ZENFISH


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## Elkmor

Edward,

Your PPS recommendation is 5-10 ppm of Mg. Can You comment?

I suspect Ca/Mg issue on my plants (RO user) and need more info on it.

My Mg/Ca is 4/25 and I have curly leafs now.


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## plantbrain

Zenfish:
That tank looks trace limited to me, switch to TMG since you have hard tap water. Add a tad more CO2. Not much, maybe .1pH unit further down.
You also need to add some more PO4/NO3.
Low nutrients and stressed plants.

Dennis, welcome to the real world of low CO2 Somewhat humbling huh? If you have not been there, just wait a awhile, everyone that's been in the hobby long enoyugh goes down this road. Many still fight it and think their CO2 must be in good shape and thus chase funny nutrients issues around.

Look at plants more, distrust test kits=> they should have to prove to you that they are accurate and correct.

Elkmore, add good CO2, add more Traces, set things up to isolate the Mg or Ca, do this by providing non limiting conditions for the other nutrients.

You can see if the Mg is the issue by doing this and adding everything but Mg, wait about 2 weeks and you should see the signs of Mg limitations.

Then look very carefully at how the plants grow and which species are effects etc. This will give you a better cause/measurement approach than the guessing and chasing after each nutrients.

It's fairly easy and straight forward.
You can do this for any nutrient easily. 

Regards, 
Tom Barr


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## Edward

Elkmore,

Consistency and Time.

Changing NO3 from 30 ppm to 20 ppm doesn’t affect plants. But changing Mg and Ca does. You need to maintain stable levels for longer period of time and allow plants to adjust to the new conditions. 
It is easy for Ca. Dose once to 20 ppm and re check after a month or so. Mg needs to be dosed daily in rather smaller quantities not allowing it to accumulate. Plants will grow well even if Mg reading is at zero. 


Edward


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## Elkmor

Tom, Edward, thanks for advice. Just one question:

Can curly leafs be because of low Mg levels?


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## plantbrain

I have not seen any definitive patterns as of yet to that effect.
Some have suggested it goes away when they added more Mg.
Same has been said for Traces, NO3, CO2 etc. 

Few seem willing to trash their tanks/plants in a controlled manner to answer such questions. Those with ther ability to do that, don't have the curly leaf issue to begin with and have the control, those with curly leaf, often do not have the control the begin with(ability to confidently rule out another possible confounding cause). 

Later this summer I'll have time to set and few things up for Mg. 


Regards, 
Tom Barr


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