# Too much Potassium



## werner

For a long time I have suspected that high potassium levels were causing deformed growth in some of my plants- specifically _Nesea crassicaulis_ and _Ammania senegalensis_. Apparently these species are sensitive to K.
















I stopped dosing K almost a month and a half ago, and have done many big water changes to get the levels down. Today I finally received a potassium test kit that I ordered. The two tubes on the left are standard solutions of 1mg/L and 3mg/L of potassium (it's hard to see the turbidity because of the camera flash.) The tube on the right is my aquarium water.  Obviously a little high.









I'll be doing more big water changes to try to get it down near 2mg/L (recommended level) to see if my plants improve. I'll update with any changes since it seems that others here are having similar deformed leaf growth.


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## Wö£fëñxXx1

Looks more like a carbon issue than a K+ issue, I would focus more on the gas, you will get better results than thinking it is K.
C02 is harder to get right than one may think, dose some Flourish Excel for a few days and see if you can not tell a difference in growth patterns, then you will know to focus more on C02/carbon.

Simply give the plants what they need-KN03, KH2P04, Trace based on water volume and light intensity, the rest is C02... its that simple, C02 is the hard part, promise.


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## Salt

Wö£fëñxXx said:


> &#8230;dose some Flourish Excel for a few days and see if you can not tell a difference in growth patterns&#8230;


_Nesea_ is a slow growing species and a few days will not reveal a difference.



Wö£fëñxXx said:


> Simply give the plants what they need-KN03, KH2P04, Trace based on water volume and light intensity, the rest is C02... its that simple&#8230;


This seems to be a common fallacy with some forum posts as well as some techniques, including EI. You said "the plants," as in "plants in general." We are not talking about "plants in general" here... we are talking about a *specific species*, in this case, _nesea crassicaulis_, and also _ammania senegalensis_.

kekon did some testing with conclusions to support potassium causing calcium deficiency in some specific species:

http://www.aquaticplantcentral.com/forumapc/science-of-fertilizing/31880-50-ppm-ca-and-still-ca.html

In fact, increasing CO2 may only make the problem worse. It may have to do with "driving" certain species of plants too hard (high light, high CO2, high macro and micro levels), as these specific species may have a limit to their calcium (and possibly other nutrient) uptake rates.

I too have _nesea_ showing calcium deficiency, like werner's pictures. I usually reconstitute my RO water with calcium carbonate + potassium carbonate to achieve my desired levels (right now 60 ppm as CaCO3 for GH and 40 ppm as CaCO3 for KH), and I am going to stop dosing the potassium carbonate starting with next week's 40%+ water change. I'm planning on targeting 60 ppm as CaCO3 for GH and just letting the KH fall where it will. I'm more confident doing this with recent findings that even 0 KH doesn't have ill effects on fauna or cause "pH crashes."

Right now my weekly potassium tests using Lamotte's Potassium Test Kit show that my levels have been consistently below 6 ppm.

You could use this test werner to determine where your potassium levels are between 6 ppm and 50 ppm. You need a white surface to hold the tube over, a bright overhead or ambient room light, and some distilled or RO/DI water. I bought mine from Clarkson Lab.


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## Wö£fëñxXx1

Salt said:


> _Nesea_ is a slow growing species and a few days will not reveal a difference.
> 
> This seems to be a common fallacy with some forum posts as well as some techniques, including EI. You said "the plants," as in "plants in general." We are not talking about "plants in general" here... we are talking about a *specific species*, in this case, _nesea crassicaulis_, and also _ammania senegalensis_.


The common fallacy is feeling the need to even respond to a post like this riddled with guess work that only adds more confusion to the orginal topic.
I have grown both Nesea crassicaulis, and Ammania senegalensis, so I am well aware of thier growth patterns, these plants are no different than any others I have grown and if you give the plants what they need and the conditions are right, you will in fact see a difference in a few short days to a week. 
I can grow some plants!

You mow your lawn, chop every plant in the yard sling clippings all over, run over it with the mower and if conditions are right, rain a couple times a week with some sunshine/light, it needs it again in a week, weeds, same thing. if you get no rain for a month then the mowing is much less, stunted growth.



Salt said:


> kekon did some testing with conclusions to support potassium causing calcium deficiency in some specific species:
> 
> http://www.aquaticplantcentral.com/forumapc/science-of-fertilizing/31880-50-ppm-ca-and-still-ca.html


Who, did what? Run with that if you choose...



Salt said:


> In fact, increasing CO2 may only make the problem worse. It may have to do with "driving" certain species of plants too hard (high light, high CO2, high macro and micro levels), as these specific species may have a limit to their calcium (and possibly other nutrient) uptake rates.
> 
> I too have _nesea_ showing calcium deficiency, like werner's pictures. I usually reconstitute my RO water with calcium carbonate + potassium carbonate to achieve my desired levels (right now 60 ppm as CaCO3 for GH and 40 ppm as CaCO3 for KH), and I am going to stop dosing the potassium carbonate starting with next week's 40%+ water change. I'm planning on targeting 60 ppm as CaCO3 for GH and just letting the KH fall where it will. I'm more confident doing this with recent findings that even 0 KH doesn't have ill effects on fauna or cause "pH crashes."
> 
> Right now my weekly potassium tests using Lamotte's Potassium Test Kit show that my levels have been consistently below 6 ppm.


Your powers of observation are riddled with error and guess work, plants can only grow so fast and that is it, but if C02 is good especially in high light the plants will show vigor, very colorful and strong, as long as there are no shortage of nutrient's, with much light, comes the need for more nutrient's.
What do these numbers tell you? anything? do you still have plant issues and uncertain as to why? so you guess at this and guess at that.

Salt, take another real good hard look at the pictures he has posted, those plants are stunted, washed out and almost burnt up, blistered even, and you "think" it is K+? or calcium so you buy a Lamotte? more guess work. plants are the ultimate test kit, it does take a little practice to learn to read them though, test kits lie, plants never lie [smilie=i:

It is not rocket science, growing plants is actually very easy, we are not building piano's here but growing weeds under water, your post is proof that C02 is a little more complicated to get right than one may think, getting C02 nailed down is the hardest part of growing plants without having algae issues or stunted burnt growth, most posts like this I see, I usually pass right on by because it turns into a headache trying to get folks just to understand that C02 is 90% of all plant related issues.

You believe in the "pH crash" myth like many do? it is a hoax, myth! learn to master the light, C02 w/areation and you can rule out that line of thought.

[URL=http://www.plantedtank.net/forums/general-planted-tank-discussion/32365-low-no-kh-low-ph-without.html]Low or no KH and low PH without a "crash"?? - The Planted Tank Forum[/URL]

Sorry if my post seems a little harsh, the subject is old shoes and does not focus on the needs at hand.

I have been using RO/DI for a few years now, I have yet to see a need to add any Mg, Ca, crushed coral or even sodium bicarb to the water, it is not needed, I placed my focus on the basic needs of the plants, N03, P04, TE, C02/light and aeration, stop doing guess work & prove it to yourself you owe it to your plants and the people you are trying to help. If you are traveling and get lost, while asking directions you want someone the knows what they are talking about to help you eh. :wink:

Here is a simple test for you to try, so you can prove it to yourself:
Keep it simple, use only the basics, N03, P04, TE, C02, light.
Use a 10g tank, you can get one from waltons for 8/10 bucks add a little peat and substrate of your choice, preferably something soft like kitty liter, Flora Base or ADA AS, add mulm, use RO/DI or RO/DI+tap, and fill the tank with plants, add a dozen or so cherrie shrimp, dose the tank with only KN03, KH2P04, Trace either daily or alternate, it doesn't matter and start C02, grab a bottle of excel, you will need it till you get an understanding of C02.
learn to read the plants and the shrimp, no test kits at this time.
Use the Excel to aide you in carbon only when you see a need and you "think" you are deficient in Ca or Mg.
Master the C02/light relationship, and use areation daily at lights out or when you see stressed shrimp, they will start to swarm like bee's.
I guarantee you do a tank like this successfully and you will learn the needs of the plants and critters which is NPK TE C02 light and the money you spend on those snazzy high dollar test kits that lie and still leave you confused as to what the problem with your plants may be, you can buy a nice 2213 filter for the tank, you don't need a bunch of numbers to tell you how to grow plants, you need hands on experience.

Think ahead, add mulm to the new tank and have a seeded filter ready to go when tank is ready to build.
If you have a KH/10 out of the tap, cutting it 50/50 with RO will give you a KH/5, thats how it works, so if you want a KH/2 cut tap 80/20.

:focus: 
Focus on your C02 werner while giving to the plants N03, P04, trace, don't over do it on the light, your plants look burned.


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## Salt

I typed up several variations of replies to Wö£fëñxXx's third post in this thread, but ultimately I think it's best not to reply at all. That is a very long and attacking post and it just has too much negativity in it for me to reply in a positive and friendly manner.

But I will at least say that this statement alone...



Wö£fëñxXx said:


> You believe in the "pH crash" myth like many do?


...shows that you have not understood my post. How can you read this:



Salt said:


> I'm planning on targeting 60 ppm as CaCO3 for GH and just letting the KH fall where it will. I'm more confident doing this with recent findings that even 0 KH doesn't have ill effects on fauna or cause "pH crashes."


Then conclude that I meant the total opposite of what I posted?


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## werner

Great! I've started a flame war.

The rest of my plants are doing fine, I'm adding plenty of ferts (now using CaNO3 instead of KNO3 and Na2HPO4/NaH2PO4 instead of KH2PO4), iron, traces, lots of CO2 (pressurized), etc., etc. I no noob. Just trying to get the problem with these particular species under control.



> In fact, increasing CO2 may only make the problem worse.


After reading responses to many posts that describe the solution to all sorts of deficiency problems as "you just need more CO2", I have been increasing my CO2 over the last week to confirm that this not a factor in my particular situation. indeed, the _Nesea_ has gotten more "burnt" looking; before it was just deformed, and still had some color.

I originally had no problems with the _Nesea_ when I added it several years ago. It grew like a weed. I believe that the slow buildup of K (I used to dose K2SO4 too) has caused the problems (by blocking Ca). The _Ammania_ was added 3-4 months ago and grew deformed immediately.


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## jude_uc

Do you have any idea what your calcium levels are? I occasionally have had similar problems (though not as drastic as what you are seeing) and calcium seemed to help. It's hard for me to say that the potassium is directly a cause because I use incredible amounts of fertilizers with potassium in them (though I've never tested for potassium). CO2 is, of course, great at making your plants grow quickly and look pretty (mine get an almost waxy sheen), but contrary to what Barr and his disciples push, I don't think it is really a cure for all ills. One thing I would look into, if I were you is whether your plants are really getting enough traces. I was always quite conservative with them and tended to have lots of problems. Now I'm adding > 1/8 tsp every other day (for 30 gallons) and things look much nicer. I think that when we drive our tanks hard, we wind up seeing fairly strange deficencies... a bit of gh booster + a bit extra trace mixture might go a long way.

-Adam


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## werner

*Calcium*

I have fairly hard tapwater: 39.8-69.9 mg/L calcium and 10.6-18.1 mg/L magnesuim according to the city's water quality report. I mix the tapwater with RO/DI water to keep the Mg low; my calcium is about 30 mg/L now. I am also dosing CaNO3.

Traces are fine- I use Flourish trace at about 1.5-2 times the recommended dosage.

A couple of threads that may explain my belief that this is a potassuim issue:
http://www.aquaticplantcentral.com/.../20440-wet-thumb-forum-no-more-potassium.html
http://www.aquaticplantcentral.com/...8525-wet-thumb-forum-potassium-problems.html?


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## MrSanders

> but contrary to what Barr and his disciples push, I don't think it is really a cure for all ills.


 LoL..... I thought he long left because he was angry??? Still watching the forums sending the second line in to fight for him? haha......

This is really a bit out of line dont you think? fight wars about opinions elseware, the one posting a question is trying to get help to grow plants better.... not hear a debate about what is right and what is wrong..... Bring it to the barrreport if you want to debate


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## MatPat

Well, I have to agree with Craig on this. Too many folks (myself included) look to blame deficiencies or excess nutrients instead of CO2. I have had Ammania gracilis and Nesea pedicellata (granted we are talking about N. crassicaulis in this thread) look similar to these photos and everytime it was due to a CO2 issue. 

For nearly three years I had well water and no problems with these two species of plants. Since moving to Ohio nearly two years ago and using a a public water supply, I have had similar issues to these even though my CO2 calculations (LaMotte Alkalinity kit and Hanna pH meter) say I have upwards of 200ppm of CO2. 

I have used various methods of CO2 dispersion in my tanks (DIY Reactors, Aqua Medic Reactor 1000, bulling inot a canister filter, mist, etc) and cannot seem to induce fish stress due to high CO2 levels her in Ohio. In Maryland, somewhere in the 35-40ppm range always gave me gasping fish. Yesterday I left the lights off in my 75g all day with the CO2 running at aver 3bps...I had no fish stress when I returned home at 10pm in the evening! 

I believe CO2 issues are proving harder to correct than some folks give credit for.


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## MrSanders

Guys lets try to follow Matt's lead with this one, keep it away from attacking negativity.... and try to be productive and remeber the goal here is to HELP the poster fix thier problems..... 

Some good advice matt, and expierence's I to have found similar things here in Ohio for what ever reason.... I REALLY have to crank the gas to get fish stress, and often find my self shy'in off of it for fear that I may be adding to much, or that I am dropping the PH to low. I just recently started buffering my KH up to 4dh because I was having my PH dropping into the low 5's and was getting nervous about it like I mentioned above...... 

Though through all of that, usually no fish stress..... and Often times stunting issues, CO2 is definantly one of the most tricky ones to get down for me.... Espically since there just is no good way to measure it, I am hopeful though that the drop checker method may help us to get to a level where it just needs very fine tweaking quicker though.

I thought the same about the degassed tank water, but here when I take a sample of my tank water out and let it degas it has a PH of 7.4.... Well at the end of the day when my CO2 is about to shut off and I test the water, the PH is 5.9.... Thats a 1.5 unit drop in PH and I have no fish stress and poor plant growth..... Pretty good evidance that method of testing can be tossed out the window.....


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## kekon

I'm sure there are certain factors that make it possible to have low Ca moderate K (10..15) and no issues with burning, twisting etc. The problem is how to find these factors. In the past i had GH = 3, very low NO3 (2..5 ppm) and very low PO4 (0,1 ppm) and my plants grew very fast; i had to do massive prunnings every week. I used 3 commercial fertilizers: one for changed water (it consisted Fe, Mn, B, Zn, Cu, Mo, Si, Co, Ti), one for daily dosing (Fe, Mn, B, Zn, Cu, Mo) and NPK fertilizer (also dosed daily). The NPK fertilizer had very little N (NH4 form). 
A week ago i did another experiment: i upped my NO3 to 20 ppm from Ca(NO3)2. Within 3 days my umbrosum looked like dead. It looked as if it was 
pulled out from my tank, put in the fire and planted back in the tank - horrible. So i did the opposite - stopped to dose NO3 at all (i also lowered PO4 to about 0,2 ppm). When NO3 dropped to about 5 ppm the plant began to grow healthy. Also my alternatera reineckii was producing new, nice leaves without any deformations (K is still 10 ppm). However, growth is still very slow.
I came to the conlusion that NO3 excess might induce Ca deficiency as well. As far as i know NO3 is converted to NH4 in plants tissues. From the hydroponics literature i know that NH4 excess also causes Ca deficiency so maybe high NO3 makes high NH4 in plant tissues.
Anyway, there may be other elements (titanium, silicon ?) that can have effect on overall N:K:Ca ratio thus, causing problems with Ca.


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## ruki

This is a very tricky one.

My perspective, not trying to start a flame war here, is that Barr's EI approach works really well for most plants, but not all of them. I switched over and got much better results for most plants, but my Java fern did much worse in this EI environment.

This observational approach we all tend to use by default has limitations since we humans are really good at finding patterns, whether they are accurate or not. To get a better understanding of what's really going on, it would be helpful to have multiple single species tanks with this problem plant and try different techniques on it. Arguing one way or another without experimental tanks to give really solid evidence is a bit like pi55ing into the wind.  

I wish you luck with this problem plant. Am curious as to what is going on, but will be respectfully sceptical of conclusions unless it can be demonstrated in control -vs- treatment experimental tanks.

This is a most interesting hobby.


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## Zapins

I had the same problem w/ some of my plants. Looked like calcium deficiency, but I believe it was too much potassium that was causing it. 

I had my water tested by plasma emissions spectroscopy at my college's lab and it was about 500ppm 

Caused symptoms exactly like the pics posted above, except at my levels it was evident in a few of the other stem plants, in addition to my nesea/amania.

After several water changes, and drastically reduced K dosing, the plants returned to normal. CO2 was not changed during this time.


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## werner

> Barr's EI approach works really well for most plants, but not all of them.


I'm not using the EI method (my dosing is more along the lines of the PPS method.)



> I came to the conlusion that NO3 excess might induce Ca deficiency as well.


I keep NO3 fairly lean- usually around 5 ppm, so I don't think this is an issue in my case. If I don't see an improvement after I get my K down to reasonable levels, I'll pursue the possibility of other elements causing a problem (or maybe just throw out the plants and be done with it!)



> I had the same problem w/ some of my plants. Looked like calcium deficiency, but I believe it was too much potassium that was causing it... I had my water tested... 500ppm


Yikes! When I finally was able to test for K, it was about 30-40ppm. I don't even want to guess how high it was originally, before a month and a half of water changes and no K dosing.


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## kekon

Now my nitrates are about 2 ppm after WC and now i dose... NH4 from NH4(OH) - very unpleasant, corrosive and very stinking liquid. Some time ago i dosed NH4 - 0,5 ppm daily (NH4NO3) and i didn't have any algae. Some people i know have done it for months with good results.


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## BryceM

After reading all this I pondered the value of adding to it. Despite something telling me not to, here goes:

First of all, Wö£fëñxXx grows some pretty nice plants and there is a ton of experience behind what he offers (maybe not so politically correctly) but all the same......

Second, even the high-end test kits (Lamotte, etc) have a tendency to lie. Even if they don't, our abiltiy to interpret the meaning of the result is EXTREMELY limited. Many test kits cross-react with other compounds and only give reliable information when the nutrient in question is present by itself in distilled water. Reporting observations that occur with a certain concentration of a nutrient is almost useless, unless verified by independent means (several tanks with identical conditions, controlling for a single variable). This is a basic scientific principle.

Third, water chemistry is HIGHLY variable around the country. People add all sorts of random additives, the tap water varies widely, and one trace is not equal to another.

It's ok to make a statement like "XXX ppm of nutrient Y caused symptom Z in this plant". But, you need to have independent evidence that the same level of nutrient Y will produce the same symptom in a different tank. Otherwise, the evidence is anecdotal. It may be perfectly valid in the person making the statement's setup, and perfectly invalid in another person's setup.

Our ability to accurately measure CO2 is almost non-existent. The biochemstry behind fish stress is complicated, at best. The only time I've ever had issues with excessive CO2 is when introducing new fish. I suspect most fish can tollerate concentrations well beyond the so-called optimal 30ppm level (as if anyone was ever able to measure that accurately).

All other things being equal, more CO2 will do more to enhance plant growth than any other single element. Buffing up any other nutrient will not overcome a CO2 defficiency in a high-light setup.

Might Werner's issues relate to K? Maybe, but I need a WHOLE lot more proof. Given the current state of the discussion, CO2 is far more _likely_ to be the culprit.


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## jude_uc

I'm not saying that potassium might not be causing problems, but it isn't beyond the realm of possibility that there are subtle reasons why most people do not see this and some people do (especially in certain sensitive plants). As kekon suggests, I would imagine that there is some other factor (a trace nutrient or perhaps even the balance of macronutrients and the mesonutrients (Ca, Mg)) allows the problem to manifest. This may explain why zapins was able to fix it with just reducing K (that is, potassium really can cause problems) but at the same time, other people with very high K levels never see a problem. I also agree that without comprehensive studies, no one will know, but that doesn't detract from less certain experiments we can do at the hobby level. All I can say is that it does seem that when my Ca and Mg are relatively high, even though I use tremendous amounts of K, I don't see problems. However, when I've had softer water, I have seen some problems in some of my plants, but not to the degree some posters have. Therefore, I don't think it's an unreasonable hypothesis that extra Ca and Mg can counteract the effect of abundant K. This could be tested rigorously, but I do this as a hobby and don't have the money to set up multiple test tanks; I can barely afford the upkeep of my normal tanks.

-Adam


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## kekon

I think CO2 is not an issue. CO2 deficiency doesn't cause leaves twisting and curling. I kept 50 ppm CO2 in my tank and it didn't help at all. I can't see any difference between 10 ppm and 50 ppm CO2 apart from stronger pearling. The problem described here is caused by calcium-potassium-nitrogen metabolism. These elements have influence on each other. The only problem that i noticed caused by low CO2 were leaves wilting and slower growth.


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## Glouglou

Second Kekon on this, CO2,to my knowledge, do not cause the malformation (twisting & curling) of leaves.

But low Calcium levels or Calcium uptake blockage do.

These element in excess or missing from the solution will improve or stopped Calcium intake...

> K > Na > Mg > Ca

Boron can have an effect on calcium consumption but the level is different for each plant and the line between helping or be detrimental to calcium uptake is really fine


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## kekon

The point is that K must be high but low NO3 (or NH4). I upped K levels and... now i don't have stunting. Now it proved in my tank that too much nitrogen cause terrible leaves deformations.
I asked Seachem why they give so much potassium in their product Equilibrium (Ca 16, Mg 5, K 40).
They told that such high K level would not cause Mg or Ca deficiency and i noticed they were probably right.


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## algaehater

Is there any truth that excess potassium blocks the uptake of ca? my hygrophilla tops looks burnt with leaves curling down, the smaller hygrophilla plants look lush and green??? also my rotala r has stunted and has wilted leaves (wilts more in the mornings).

Since i have change to ei my plants are looking worst than ever ! even my amazon plants is all curly and wilted.

I wonder if im overdosing potassium ? i did read low co2 will cause plants to wilt so i have up the co2 again.

What i dont understand is why has all my algae dissapear with my plants doing so poorly you would think that algae wouls start to set in ?


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## Avalon

algaehater said:


> Is there any truth that excess potassium blocks the uptake of ca?


No. I've heard about everything, but I've yet to see any conclusive evidence. I've noticed myself that excess K seems to hinder plants, but again, that's a casual observation with no scientific method used. I certainly don't blame it on Ca.

Here's the thing: EI users must be careful with the large doses. If you aren't tailoring EI to your needs, you're likely to have problems. I know what my plants need between the dosing period, and I dose just a bit more, scaling with plant mass. Why dose more? It serves no purpose other than wasting fertilizer. I only dose K at every water change, or about once every 5-7 days if I have to go longer without a water change.

But you mention leaves curling down...this is usually an indication of low CO2. If your CO2 is already at borderline levels, accelerating plant growth with ferts will cause an increase in CO2 uptake, creating an overall deficiency.


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## Zapins

K doesn't usually block mg/ca uptake unless it is present in ridiculously high levels (hundreds of ppm).


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## algaehater

Thanks for the replys, I will up the co2 and up the traces aswell just incase theres is a shortage.


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## Mr_docfish

Zapins said:


> K doesn't usually block mg/ca uptake unless it is present in ridiculously high levels (hundreds of ppm).


This has been my issue for sometime now... been using leaf zone for some time with the addition of KNO3 and the plants were showing Ca deficiency.... from Gurus, I have been told that I have a CO2 or water flow deficiency...... increased both, tested CO2 levels, Ca levels, NO3 levels etc... and the only thing I could not test for is K levels..... but from my calculations (I don't do enough water changes) the K levels would be above 300ppm+ after 3 weeks (assuming that if the plants I keep don't utilise as much K as others... I keep Aponogetons mainly, and crypts... almost no stem plants).

until I get a K test kit (http://www.aquaticplantcentral.com/forumapc/fertilizing/58309-potassium-test-kit-brand.html), I cannot prove my hypothesis (nor could many others... that is why there is still an argument over this topic of K vs Ca) so if anyone can help me get one into Australia for under US$100, this annoying theory will remain annoying....

btw, after changing fertiliser brand (to one lower in K), things are looking better already...and it has been more than 3 weeks since my last water change.... at this point the rainbows would have been freaking out and the affected plants would still be curled up......not the case now....


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## Zapins

I also got potassium stunting in one of my tanks. When I had the water analyzed by the lab at my school there was 500 ppm in one and 800 ppm in the other if I remember correctly. I did several water changes and that helped the problem too.


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## Mr_docfish

After reading this whole thread and others relating to the same topic of K levels... I find that we are never going to prove or disprove any of these theories until correct/accurate testing procedures can be made available to the hobbyist, or facilities that are economical for us to use... 
and on the other side of the coin, Ca levels in the gravel are never considered in some cases (mine is deficient to start with... somewhat too late for me to change it) so those with high levels of K (more than 200ppm) might not have a problem, if the roots are still able to uptake Ca from the gravel, regardless of the K levels in the water....

also, in my recent discussions with some plant gurus (that feel I have a CO2 deficiency), they avoid the question of why some of the fish species in the tank are affected by a chemical that can affect the nervous system, at the same time that the plants are affected, by seemingly a Ca deficiency. Correct me if I am wrong, but if you immerse fish in a very high K level (low Na), this will cause an imbalance in the cellular Na:K ratio.... I have Rainbows, Botia and SAE in the tank, and I can see a gradual decline in the Rainbows as they start freaking out more and more, while the other fish are not affected.... this is the same with plants in the same tank... only a few are affected.

just to add a little science to this, (though the plants used in this study were higher order algae) the effect of K on Ca influx was measured, but for only up to 100mM of K..... the Ca influx increased as the K increased until about 20mM, then it dropped and continued to drop until the end of the test at 100mM of K in solution... I wish they would have continued the test further - this is the PDF of that paper :: http://www.plantphysiol.org/cgi/reprint/100/2/637.pdf look for Fig 5
unfortunately there has been very little done in this field, so this is the only info I could fish on the net... I will have to ask friends still at Uni to look for more info, if it is there....


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## BryceM

The fact that community tanks can exist at all is a testament to the vast ability of fish to acclimate to their surroundings. Still, it's important to remember that the physiology of one species can be vastly different than another. High CO2 levels affect my sidthimunki loaches while other fish are perfectly fine. It's just that unusual conditions overcome the limits of certain organisms ability to cope before others. Plants are no different.


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## DiogoReis

Hi people, sorry to post here in 2006 topic but this was very interesting topic.
I have the same issue and i dont find information about it... I cant solve my problem...
The conclusion was to low the nitrates?


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