Calcium Carbonate vs Calcium Sulfate

TheWizard

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I recently switched to using an RO system due to severe inconsistencies in my tap water quality. I've been using GLA Ultimate GH booster. My assumption was the calcium would also raise kh, however it's calcium sulfate. Is there a significant difference between calcium sulfate and calcium carbonate for the sake of calcium? Are there negative effects of having a kh of 0 that I should be worried about besides the lack of buffering ability?
 

Christophe

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Calcium is calcium, from sulfate or carbonate. I'd think you'd want at least a little carbonate in there for buffering.

Consider looking for potassium bicarbonate for that. It's available from home brewing/wine making shops, as well as online. You could use baking soda (sodium bicarbonate) as well, but that adds sodium, which might not be very desirable if you've already got some in your water.
 

TheWizard

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Calcium is calcium, from sulfate or carbonate. I'd think you'd want at least a little carbonate in there for buffering.

Consider looking for potassium bicarbonate for that. It's available from home brewing/wine making shops, as well as online. You could use baking soda (sodium bicarbonate) as well, but that adds sodium, which might not be very desirable if you've already got some in your water.

I'm using ADA Amazonia, it buffers the ph pretty well, and it reduces kh. So I'd just be adding it for it to be buffered out.
 

Christophe

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Yes, it does. Part of the reasoning behind it is to help your tank water to tend a little softer and more acidic, to imitate so many Amazon environments. But if you're using 100% RO, you're already there.

Are you using full RO, or mixing with some of your tap? To what extent? Blending can keep some of what your tap provides, including carbonates, while mitigating some stability/suitablilty issues it might have if it was used full-on.
 

TheWizard

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Using 100% RO. The KH and GH are inconsistent as all hell. One day I'll have a KH/GH of 6/6 and the next it's off the charts. I dose GH booster (4tbsp into 35g, roughly 6dgh)and then use Thrive+ for dosing. Twice a week when dosing a tbsp of GH booster to make sure there's Ca/Mg in there.
 

Christophe

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Just add the GH booster on water changes -- add enough to bring the water you're adding up to your target GH. Not that much Ca or Mg is actually consumed. Adding more mid-week is not really necessary.

You could stand to add some KHCO3 also, just to have a bit of buffer in the system, even if the Aquasoil locks up some of it. Add it in the same way you'd add GH booster, just at water change. After a couple months, the effect of the aquasoil fades off anyway.