# Still need to dose Calcium and Magnesium with Onyx Sand?



## Piscesgirl (Feb 25, 2004)

If Onyx Sand is Gray Coast Calcite, must one still dose Calcium and Magnesium or are the plants able to get enough from the substrate?


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## Phil Edwards (Jan 22, 2004)

If you're not dosing CO2 then I would suppliment Ca and Mg. Even if you are dosing CO2 it's still a good idea to add Ca and Mg. You just might not need as much.

Regards,
Phil


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## Piscesgirl (Feb 25, 2004)

I use DIY Co2 on that tank (20 gallon) and it does well...kh of 6...just was thinking perhaps the Onyx was enough? I do dose a little magnesium (epsom salts) and calcium (calcium cloride) although by no means consistently or scientificaly (squirt here, pinch there).


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## plantbrain (Jan 23, 2004)

Probably fine then.

SeaChem EQ for tanks works very well and considering you really do not need much and it has everything in one product, I keep using it.

K2SO4
CaSO4
MgSO4
FeSO4
MnSO4

Regards, 
Tom Barr


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## Piscesgirl (Feb 25, 2004)

Thanks Tom and Phil


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## Edward (May 25, 2004)

Hi
Onyx usually leaks lot of *Mg* and Ca. You can check with a GH kit after one week and compare it to your tap or what ever you use as source water. There is no need dosing extra if your dGH goes up in the aquarium. 4.4 ppm of Mg makes 1 dGH and 7 ppm of Ca makes 1 dGH. 
What is your tap dGH?

Edward


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## Piscesgirl (Feb 25, 2004)

My tap is nearly devoid of any GH/KH, very very very soft. My 20 gallon has a kh of 6 with the Onyx (mixed with gravel not a lot of substrate, I'd say about an inch).


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## plantbrain (Jan 23, 2004)

Sounds like Neil's Tap add some SeaChem EQ, 1/4-1/2 teaspoon once a week will address it.

500 gram bottle will last a very long time.

Regards, 
Tom Barr


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## Piscesgirl (Feb 25, 2004)

I have the EQ, but it doesn't dissolve very well -- and with the Onyx raising the Kh so much, I figured maybe I don't really need to add the Mag/Cal. I do add Potassium Nitrate, Potassium Sulfate, and Potassium Phosphate (Greg Watson).


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