A look at GH and magnesium.

W

WinstonCourt

AC Members
May 30, 2010
148
0
0
65
My water is pretty soft for some needs. At about 30 ppm calcium, the plants suck it down pretty fast. Total hardness, GH, is 130, the plants pull this down quickly also.

For calcium, I use calcium hydroxide reacted with vinegar to form calcium acetate and introduce it to the intake of an AquaClear filter. For GH, I use magnesium sulfate.

I started thinking about this magnesium sulfate. Chucks aquarium calculator will give you the amount of it to raise magnesium to the level you desire, it does not allow you to figure how much sulfur you are dumping into your aquarium. Since MgSO4+7H2O is magnesium sulfate, I wondered, what percent of this is sulfur?

Atomic weights:
Mg = 24.3050
S = 32.065
O = 15.9994
H = 1.00794

So, 24.3050 + 32.065 + (11 x 15.9994) + (14 x 1.00794) = 246.47456

then: 32.065/246.47456 = .1300945 = 13.00945% sulfur
and: 24.3050/246.47456 = .0986105 = 9.86105% magnesium

So, it appears for the benefit of the magnesium, I am dumping a butt load of sulfur into the aquarium. Now, I have no problem with this, I am just shocked at this large figure of sulfur.

So, I did the computation for magnesium chloride MgCl2:

Atomic weights:
Mg = 24.3050
Cl = 35.453

24.3050 + (2 x 35.453) = 95.211

24.3050/95.211 = .2552751 = 25.52751% magnesium
(2 x 35.453)/95.211 = .7447248 = 74.47248% chlorine

Almost 2x as much magnesium but a butt load of chlorine. No better, perhaps worse.

So, why aren't we using magnesium citrate to increase GH? Magnesium Citrate = C6H6O7Mg. The carbon, hydrogen and oxygen would do no harm and, most likely, serve as some form of carbon for the plants.

Example: http://www.amazon.com/Calcium-Magnesium-Citrate-powder-Ounces/dp/B0002PU648

At 11.33561% magnesium and none of the sulfur or chlorine, seems like the ticket. Might like to check my figures for errors.
 
i was curious about the amount of sulfur that i dump into my tank before as well

i use
Barr's GH Booster which contains: Potassium Sulfate, Calcium Sulfate, Magnesium Sulfate once a week with a water change, and potassium sulfate every other day
 
HEY.

jpappy789 said:
Isn't magnesium citrate a laxative?

Not sure I would personally risk something used like this on fish.
Click to expand...

You don't get to ask a question until mine is answered. LOL

But, you do have a point, I mean, I see enough fish poo in my aquariums as it is. ROFLOL
 
Could it be that it is just more expensive than magnesium sulfate? I can't seem to find it in the same forms as Epsom salt - it's either liquid or tablet, not very easy to dose in aquariums. Even generic versions of Citroma are quite expensive compared to Epsom salts, which are used as a food for terrestrial plants also.
 
You must log in or register to reply here.
AquariaCentral.com
Top Bottom