[DeDeuce]

None of the dry ferts you are using contain any calcium. Calcium chloride and magnesium sulfate can be used to increase your waters hardness. I myself would only be suspect of this if my gH was on the low side. At a previous residence, I had plants that were exhibiting leaf deformities. My water was very soft so I supplemented with calcium / magnesium with good results.

--
Don

 

[Rex Grigg]

Calcium chloride is my choice. Dissolves quickly.

 

[Joetee]

Rex,
My KH is 5.5 and stays steady. Would deformed leaves still be the result of low calcium?
I read somewhere that someone used Tums for calcium for their snails. Would this work?

Joe

 

[Glouglou]

Calcium

Calcium ir rarely missing in freshwater aquaria but Calcium Intake can be problematic with to High or to low Potassium.
Lack or to much Boron can reduce calcium intake.
Some beleive that High nitrate is a problem.

Buy a calcium test , it’s relatively cheap and you can Know your magnesium level as a bonus...

 

[Rex Grigg]

High potassium levels have no influence on calcium intake.

KH is not calcium. It's bicarbonates.

I guess one could use Tums but I would worry about them not being pure.

 

[Glouglou]

Potassium vs Calcium

You can see that potassium have an influence on calcium uptake here.

http://fins.actwin.com/aquatic-plants/month.200401/msg00585.html

There is an antagonistic relationship between the four common alkali and alkaline earth elements such that a large excess of one element can cause deficiencies in another. The published sequence is (as I recall)
K > Na > Mg > Ca
I'm working from memory so the order of Ca and Mg in the sequence could be wrong.
Where elements on to the left in the sequence are more likely to
antagonize elements on the right. This sequence was originally published in (as I recall) Science in or about 1934.
It is well founded and widely recognized.


The mechanism for the antagonism is not simple. In the specific case of K
and Ca, there appear to be problems both at the root-soil interface and
with transport within the plant. Information on the mechanism has proven very difficult to come by. I have no reason to believe that the mechanisms
are the same in every case or that the mechanisms are simple in any case.

Common recommendations are that in order to avoid antagonistic effects
K should not exceed Ca , but some sources recommend that K can easily be 2x calcium concentrations without problems.

You can see that from more source....
http://www.sfc.ucdavis.edu/research/Calcium.html

http://aob.oxfordjournals.org/cgi/content/abstract/37/2/345

 

[Rex Grigg]

You might want to look for some of Tom's posts. He has tested it and found it's just not true.

http://www.plantedtank.net/forums/w...ml?highlight=potassium+uptake+barr#post408400
http://www.plantedtank.net/forums/w...ml?highlight=potassium+uptake+barr#post154545

I can show you plants that refuse to grow with any measurable levels of potassium in the soil. Does that mean that potassium is lethal to plants? Nope.