Dosing for GH

laka

Prolific Poster
Jan 21, 2007
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Another question if you don't mind regarding my low tec plant.
Melbourne's water is 3 degrees GH according to my test kit.
I am happy with these levels for both flora and fauna in my tank.
With time (as i don't anticipate doing water changes) GH levels will drop.
I will then need to supplement GH levels.
My understanding is that 0.79g CaCl2+0.33gMgSO4=1 degree GH

This formula gives me a ratio of Ca/Mg of 7:3.

ie. I will need to add 11.85g of CaCl2 to obtain a 0.7 degree increase in GH (or 12.6ppm) and
4.95g of MgSO4 to get a rise of 0.3 degrees in GH (or5.4ppm) in 150 gallons of water.

Is this correct if i want to increase GH by 1 degree?

I note in the fertilator , if i key in 11.85g CaCl2 in 150 gallons water my Ca++ reading is only 7.74ppm and for MgSO4 4.95g gives 0.86ppm of Mg++.

My understanding is that GH test kits measure in CaCo3??
To obtain the actual Ca++ and Mg ++ in ppm you need to divide Ca by 2.5 and Mg by 4.1. Is this correct?

LAKA
 

Tom Barr

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Jan 23, 2005
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The likely problem, especially with Cl, is the build up, whereas the same effect is not present in the SO4 build up, plants will consume/assimilate both anions in tissue, but seem to be less sensitive to high SO4 vs Cl.

Note, this is mainly speculation, no one has shown this. Still, thr evil I do know and use is the GH booster or Seachem's Eq.

Both of which use all SO4's for the anions in CaSO4, MgSO4, K2SO4, FeSO4 and MnSO4. But a little Cl is not bad and helps, same with a little sodium, but it should be fairly low. So adding some KCl, or CaCl2 every so often will not hurt too much.

Adding the GH booster works very well. I really have not done enough with Cl isolated to say much with many species.
Same with Zn, MN, Na, SO4, etc.


Regards,
Tom Barr
 

laka

Prolific Poster
Jan 21, 2007
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Thanks for the advice on Cl Tom. I do however need to know if my dosage calculations are correct for increasing GH using CaCl2 and epsom salts.
LAKA