# Is there a right answer for levels of Ca, Mg, and GH ?



## aquageek (Sep 25, 2011)

So I've been struggling over a couple questions I have about what are some proper levels for different nutrient specifically Ca and Mg.

I've been reading that levels of Ca in a planted tank should be around 30ppm. Is this correct? I've also read that a GH of around 100ppm is ideal. Wouldn't this mean ideal Ca levels would be around 75ppm and for Mg 25ppm???? I know the ratio between the two is suppose to be in the 3:1 to 4:1 area. At least on that almost everyone agrees. I'm just so confused at this point on the right ppm. The more I read the more conflicting ideas there are for the right levels?!!?

Please share what your opinion or the right answer is, if there is one!! Or what has worked for different people. Specifically in high light tanks with CO2 injection.

Help!


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## aquageek (Sep 25, 2011)

*BUMP* No input on this?


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## Silvering (Jun 10, 2011)

Go read the MCI threads. Stickies are sticky for a reason! 

I wouldn't bother worrying about it unless you have (a) some kind of deficiency showing up or (b) some kind of algae showing up. Your underwater ecosystem will tell you what it needs, so you don't need to angst over the numbers. Just learn to speak Plant.


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## aquageek (Sep 25, 2011)

That's ok, many people on another forum were extremely helpful about the differing opinions on many sites or stickies about the right levels of Ca, Mg, and total GH. Thanks for the help...


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## OTPT (Sep 27, 2010)

But does the help in "other forum" help end the confusion?

You got no answer here probably because no one knows it for sure.


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## K Randall (Nov 23, 2004)

I can tell you that in the wild, even when you are talking about one particular species, you will sometimes find the plants in a wide range of conditions, both based on the locality and the time of year you visit. That's for ONE species. When you then try to make generalizations about planted tank communities, you're pretty much on thin ice.


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## aquageek (Sep 25, 2011)

I had figured there was no perfect answer as is true with most chemistry of a planted fish tank.

I've searched and searched and with so many very differing opinions of what's right I figured I would ask everyones individual opinions of what works for them or if I was missing something. Ask the audience 

ca:mg....... 30:10 or 75:25 or 100:30, and did anyone notice a disadvantage/advantage to any of them?

I'm blessed/cursed with ultra soft water( Ca:30 Mg:0 dKH: 2.5. So I get the choice of keeping things in the low end or dosing them up. I just didn't know what people think.

Maybe I asked the wrong question to start. Its just tough when nobody starts a convo and I just get sent to a sticky.... not to mention I don't even know what an MCI thread is or where to find it?

My tank does very well for being only a year into this but I'm just hoping to improve it and my knowledge. I wanted to start with is question.


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## Skizhx (Oct 12, 2010)

I can't answer your question because I do not know an ideal ppm to aim for.

Many people with softer water either add dolomite to their substrate, or dose ferts in 3:1-4:1 ratio, as you already know...

For dosing, I seem to recall seeing people taking an "add a little, see what happens, then add some more until the problem goes away" approach.

That's the best input I can give you I'm afraid. Hopefully someone who has a more certain answer will come along to help.


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## Newt (Apr 1, 2004)

aquageek said:


> ............I'm blessed/cursed with ultra soft water( Ca:30 Mg:0 dKH: 2.5. So I get the choice of keeping things in the low end or dosing them up. I just didn't know what people think.............../
> 
> 
> > That's not very soft. My water is about half of that with a dKH of< 1. I used to use the standard 3:1 ratio of Ca to Mg. For the past few months I have been dosing equal (by volume) amounts of Ca, Mg and K2SO4. The only difference I see is less GDA on the glass. I keep my water around GH of 4 to 5 as I keep mostly tetras.


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## Silvering (Jun 10, 2011)

(Prior content removed for inappropriateness. See my apology here.)

I'm afraid I can't give you any details about the way I dose Ca:Mg because (a) I don't know my tapwater concentrations of those minerals, and (b) I don't dose those separately, they're in a trace mix that I only sometimes use. Do let us know more details about your setup and how it matures with your water and dosing, so that a year from now when another poor confused soul runs across all the conflicting information, there will be some practical results for him to look at and use to make his dosing decision!


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## Newt (Apr 1, 2004)

Silvering, IMO you come across as rather rude. This is the type of post more tyical tp TPT than APC. There was enough info in the opening post to begin offering advice. I suspect most hobbyists dont bother or care what the differences will be if you change your water chemistry.

Karen Randall's answer was very telling of what conditions are like in the wild. I am so happy to see she has joined our community here. Never realized she lived in my home State. Looking forward to her posts.


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## Silvering (Jun 10, 2011)

My apologies for hurting anyone's feelings! I must be in a contrary and combative mood today. Knew I should have eaten more for lunch, I'm always ornery when I have low energy levels and never notice 'til someone calls me on it. Please forgive any offence which I have wrongfully offered. 

Having offered apologies, may I ask what you mean by hobbyists not caring about water parameters, in good faith? This has not been my experience, and I wish for clarification. Certainly some parameters are important, if not Ca/Mg?


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## Newt (Apr 1, 2004)

I specifically meant Ca & Mg. From what I percieve from threads posted here it's typically people who have too soft or water that is too hard that begin to look into this.


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## K Randall (Nov 23, 2004)

Newt said:


> Silvering, IMO you come across as rather rude. This is the type of post more tyical tp TPT than APC. There was enough info in the opening post to begin offering advice. I suspect most hobbyists dont bother or care what the differences will be if you change your water chemistry.
> 
> Karen Randall's answer was very telling of what conditions are like in the wild. I am so happy to see she has joined our community here. Never realized she lived in my home State. Looking forward to her posts.


I've actually been a member for years. Life just gets in the way of participation. I've promised Cavan that I'll try to be around a bit more often.


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## Seattle_Aquarist (Mar 7, 2008)

Hi Karen,

Good to see you back!

-Roy
GSAS


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## Chunks (Aug 19, 2011)

I'm in the same situation with my water softness so I'll be following this thread for more info.


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## K Randall (Nov 23, 2004)

Thanks, Roy!


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## aquageek (Sep 25, 2011)

Newt said:


> aquageek said:
> 
> 
> > ............I'm blessed/cursed with ultra soft water( Ca:30 Mg:0 dKH: 2.5. So I get the choice of keeping things in the low end or dosing them up. I just didn't know what people think.............../
> ...


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## Diana K (Dec 20, 2007)

GH: Keep the fish happy. Research the fish species you are keeping, but as a VERY general guide most soft water fish thrive when the GH is under 5 German degrees of hardness, and under 3 for very soft water fish, especially wild caught. 
Hard water fish GENERALLY thrive when the GH is over 9 German degrees of hardness, and values approaching 20 degrees seem just fine with some species. 
Fish that have been captive bred for several generations are more accepting of conditions that are not within the narrow range where their ancestors came from. 
Research your fish. 

Within the appropriate range of GH for your fish there should be some of each Ca and Mg, but I do not know if the exact ratio is important. 
_______________________________________________________________
Most average aquarium plants are just fine in hard or soft water, and within that full range of GH that fish like, plants are usually just fine with. Plants seem to use Ca and Mg in a ratio somewhere around 3-4 parts Ca to 1 part Mg. 
You can test the Ca, then use some math to figure out the Mg based on the GH and Ca readings. It is not simply GH - Ca = Mg, though. 

There are some species of plants that are more particular. Research the plants you want to keep to see if you are dealing with one of the odd ones that really does need a specific value, or a narrower range of any of these minerals. 

Most aquarium keeping is not so precise. If you are in the ballpark, most fish and plants will do fine with a wide range of levels. 

Some plants use carbonates (KH) as a source of carbon. If I remember, though, they only do this if there is no CO2 available. Approximately half the aquarium plants are capable of this. 

If your water has NO magnesium, I would dose some. Epsom salt is one possible source.


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## CrownMan (Sep 12, 2005)

My water is similar to yours : 90-100GH, 70-80KH, 30ppm Ca, 0ppm Mg. In all 7 of my heavily planted aquariums (I only use CO2 in 1 small tank using EI dosing). I add about .5 tsp each of Equilibrium and Epsom Salts on water change day for every 10 gallons replaced on all tanks. I've been doing this for several years now but it took me a few years to get the levels that work for me. Using the Fertilator, I am at a 4-1 ratio of Ca to Mg.

You might have to experiment with dosing levels of Equilibrium as it adds a lot of Potassium. YMMV.


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