# Dosing Calcium Carbonate and Magnesium Sulphate?



## Pseud

I noticed wrinkled, shrivelled, deformed leaves on my plants and got hold of some CACO3 and Magnesium Sulphate from Greg. My question is how much to does in a 55 gallon tank? How do I know what my levels are already at?

Thanks


----------



## Salt

You would use a GH test kit to determine what your GH is and a KH test kit to determine what your KH (alkalinity) is.

GH tests for calcium and magnesium together. There are calcium test kits available if you really want to know how much of your GH is calcium.

It's up to you what you want your levels to be. If they are higher than you want you can use an RO/DI (reverse osmosis / deionization) system to filter your water and either mix it with tap to lower the GH and KH, or just remineralize the RO water completely.

I personally do 5 dKH and 6 dGH.

You would not want to dose the magnesium sulfate if you are dosing the CaCO3 from Greg, since his CaCO3 is not really CaCO3 but dolomite, which is CaMg[CO3]2. This increases both GH and KH at the same time. I personally don't like it because it adds too much magnesium (in my opinion). The majority of GH should come from calcium. Some people (myself included) increase GH by dosing in a 3:1 to 4:1 calcium:magnesium ratio (I do 4:1). CaMg[CO3]2 is in a locked ratio of 1:1.65 calcium:magnesium. Check out Edward's post in this thread showing what happens to Rotala Wallichii when magnesium levels reach more than 10 ppm. Additionally, it is very difficult to dissolve.

Regardless, the numbers are (I don't know how many grams per teaspoon, if you don't have a lab balance, get one off ebay! ):

To raise GH by *1 dGH* with dolomite, you would add *31.06 milligrams* per *gallon* of water. (62% from magnesium, 38% from calcium.)

This dose will also raise the alkalinity by half a degree (.49840 dKH increase).

Greg sells Calcium Chloride which will allow you to increase calcium and magnesium levels separetely.

To increase hardness by 1 dGH using calcium chloride dihydrate (which is what Greg sells) and magnesium sulfate heptahydrate (which is also what Greg sells... it's regular epsom salt) in a 4:1 calcium to magnesium ratio:

Add *79.391471* mg of CaCl2•2H2O per *gallon* of water
Add *33.275849* mg of MgSO4•7H2O per *gallon* of water

Example - to raise 40 gallons by 2 dGH:

79.391471 mg * 2 dGH * 40 gallons = 6351.31768 mg /1000 = *6.35* grams CaCl2•2H2O
33.275849 mg * 2 dGH * 40 gallons = 2662.06792 mg / 1000 = *2.66* grams MgSO4•7H2O


----------



## Pseud

Thanks for such an extensive reply. Will take me a while to digest all this, but thanks. I'll let you know how it goes.


----------



## Pseud

Alright, so I'm running into a few problems... namely cloudy water, possibly green water, some stunting on leaves of Nesea pedicellata, and Elatine triandra melting... Not sure if they're all related or not.

Dosing to keep NO3 at 10-15ppm
Dosing 1/8 tsp PO4 1 x week (don't have a PO4 test kit)
CO2 at 30-45ppm
10ml CSM+B 3 x week
1/8 tsp CaCO3 (dolomite) 1 x week

According to the fertilator, CSM+B adds 0 Ca or Mg, hence I was dosing both with CaCO3. After reading, I've discovered that CSM+B DOES contain Ca and Mg. Am I right in thinking that it does contain it in small amounts, but it's enough of a small amount to not need additional Ca or Mg? (generally speaking)

Could the excess Mg have attributed to stunted N. pedicellata and melted E. triandra?

I think I have more questions, but they aren't coming to mind right now....


----------



## dennis

Psued,

Get me a water sample and I will test your various levels. Will you be comming to the NEC, you can bring me a water sample then? If not, feel like coming up and seeing my place?


----------



## Pseud

I wont be able to make the NEC unfortunately 

I did a massive water change today, dosed NO3 back up to 10ppm, but held off on the CSM+B and CaCO3. I can bring you a water sample, but it probably will read within normal now. In any case, I'd love to see your tanks in person, so if the offer still stands, let's meet up again dude...


----------



## dkfennell

CSM+B has a very small amount of magnesium (1.4%), but no calcium.

Since CSM+B is a dry fertilizer, I don't know what you mean by 10 ml. If you are mixing the fertilizer into a solution such as "PMDD" then you may have more Mg and Ca, but you would be putting it in yourself.


----------



## Pseud

Yeah, I'm mixing 1 tbsp with 250ml of tap water, then dosing 10ml 3 x week


----------



## dkfennell

You are not getting excessive Mg from CSM+B.

I just weighed a tablespoon of CSM+B (from Greg Watson). It weighs 12.5 grams. (As Salt mentioned you should get a digital scale. The error in using tablespoons/teaspoons, etc is very great -- you will see when you get the scale. It all depends on what is considered a "level" tablespoon -- you can't replicate it. In any event they are very cheap. You can get "pocket" digital scales for much less than $30, and they give you immense cache when other people see you use them -- even to weigh letters for postage. But I digress.)

So, in one tablespoon of CSM+B there is 0.175 grams of Mg (1.4% of 12.5), or 175 mg. You dump this into 250 ml of water. I will assume it is distilled water (which of course it's not) for this calculation. This means there is 175 mg of Mg in 1/4 liter or 700 ppm Mg. You put 10 ml of this solution in your tank. 10 ml of this solution puts 7 mg of Mg into your tank (10/250 * 175)

Now I will assume there are 44 gallons of water in your tank. (Accounting for thickness of glass, substrate, etc.; in other words 80% of 55 gallons.) 44 gallons is 166.6 liters. 7 mg in 166.6 liters is .04 ppm per dose -- or an accumulation per week (not taking into account plant uptake) of 0.13 ppm of Mg. This is hardly an "overdose."

Now I don't know what is in your tap, but I would be suprised if you get an "overdose" of Mg from it. But you can get an approximation by asking your water company for its latest analytic testing results. (It may even be posted on the Web.)

BTW, if my calculations are correct, you are getting a very aggressive amount of Fe by your dosing of CSM+B. Fe makes up 6.54% of that stuff.

Cheers
Darrell


----------



## Pseud

Thanks for the numbers Darrell, there's no way that I could calculate all of that.... but what about counting the 1/8 tsp of CaCO3 which is actually, dolomite, at a ratio of 1:1.65 (I believe) of Ca:Mg?


----------



## dkfennell

OK, here are the 2 problems with your dolomite dosing: 1) It is impossible to obtain reasonably consistent amounts of a dry fertilizer by using 1/8 teaspoon measures; 2) it is very difficult to make dolomite dissolve in water.

On the 2d point, if you swish the small amount in a 1/4 cup of water, then add it, it might make it dissolve more quickly. Otherwise, it will settle to the bottom of the tank and may or may not dissolve. The same is true of gypsum (calcium sulphate). If this weren't true we could just dump egg shells, coral or pieces of blackboard chalk in for Ca dosing. I put egg shells in my daphnia tanks. The only use they are is to provide a place for algae to grow. So I throw all my dolomite in there now.

Anyway, as to calculation or how much Ca and Mg you are adding by adding dolomite, let's assume that all of it dissolves. I just weighed a teaspoon of dolomite from Greg Watson. I get 8.1 grams. I check the fertilator which says that dolomite weighs 5.2 grams per teaspoon. So I do it again: I still get 8.1 grams per teaspoon and 24.5 grams per tablespoon (3 teaspoons). (So you can see how nearly useless it is to try to take these calculations in kitchenware measurements based on someone else's (including mine) weighing.) In any event, I will use 1/4 of a teaspoon for the calculation to show your outside amount. If you think you have really measured 1/8 teaspoon, cut the numbers in half.

2 grams (1/4 teaspoon) of CaMg(CO3)2 in 44 gallons (166.6 liters) gives you 2.6 ppm of Ca (which is 21.7% of the weight of dolomite) and 1.6 ppm of Mg (which is 13.2% of the weight of dolomite). 

So you see, even if you were dosing 1/4 tsp of dolomite a week and all of it dissolved, you still would not have an "excess" of magnesium" or "calcium."

As I said earlier, I would not worry about the amount of Mg or Ca in your tank (unless your tap water is rock hard), but rather the amount of Fe you are putting in by dosing so much CSM+B. But I am very conservative when it comes to dosing traces. (Mg and Ca, however, are macronutrients.)

Regards,
Darrell


----------



## dannyfish

Will the dosing of calcium carbonate cloud the water?
it is necessary to dose?
my tank become cloudy after i dose calcium carbonate into it
Any advise?


----------



## ray-the-pilot

dannyfish said:


> Will the dosing of calcium carbonate cloud the water?
> it is necessary to dose?
> my tank become cloudy after i dose calcium carbonate into it
> Any advise?


Calcium Carbonate will definitely cloud your water since it is practically insoluble in most water.
If you are using CO2 it will dissolve after a few hours. If not, it will be in the bottom of your tank and slowly add GH to you tank.


----------



## Edward

http://sites.google.com/site/aquaticplantfertilizer/home/ca-too-low-high
http://sites.google.com/site/aquaticplantfertilizer/home/ro-reverse-osmosis

.


----------



## flashbang009

When I add it, i get a HUGE cloud. However, it clears within a minute. Back to completely clear.


----------

