EI dosing & Calcium/Magnesium


Prolific Poster
Mar 13, 2007
I am using the EI dosing method on my 135gal tank. Water volume is about 120gallons so I enter that amount in Nutri-Calc for a general EI dosing recommendation.

My question is about Calcium & Magnesium dosing

I dose the following

CASO4 - Calcium Sulfate
MGSO4 - Magnesium Sulfate​

Can someone please look at the snapshot of my Nutri-Calc setup and comment on if my Ca/Mg dosing is too little or too much?


* my "20ppm" of Calcium is the result taken from Nutrafin test kit and is in CA2+ "total calcium" level. The level of Carbonate Hardness in CaCO3 according to the instructions is gotten from multiplying CA2+ X 2.5 = 50ppm in CaCO3.

I am confused about whether or not Nutri-Calc is expecting me to put my "Source PPM" as CA2+ ... OR ... CaCO3 ... :confused:


Please help me if you can!


Daniel Morris

Lifetime Charter Member
Lifetime Member
Feb 20, 2005
Washington DC
Pockets - i can't answer your question directly re Nutri-Calc, but alternatively I wanted to show you two very educational links I just recently found.

The first discusses the relationship between Magnesium and Calcium and what you should/shouldn't be worried about, and also some dosing calcs:

The second discusses more just the calculations of dosing:

I know that doesn't directly answer your questions, but I hope you can find them useful.

Tom Barr

Staff member
Jan 23, 2005
Daniel Morris;17145 said:

Yea, good old Edward, claims things, never seems to try them. Claims other methods, ranges and rates are bad merely because he is unable to achieve success. It's not a method's fault, it's your fault.

I tried inducing the Mg+ with R wallichii, at 20ppm of so and low Ca, around 10ppm, the R wallichii still grew quite nicely.........so it's it what he claimed?
I do not see how it can be that solely.
Or Mg/Ca blocking.

We really do not see that nor have evidence of that in an aquatic water column system. That is the system that matters.

I really start to question folks when I repeat their claimed ranges.rates and cannot reproduce them.

Shalu's explaination is best.

For CaSO4*2H2O and MgSO4*7H2O, just shoot for about 3:1 ratio Ca:Mg, and about 1-2 degrees extra GH booster or about 15ppm:5ppm.

That's plenty of Ca/Mg for aquatic plants for a week and does not include other potential sources such as fish waste/CaCO3 rock/Tapwater/TMG etc.

Tom Barr