[Contrl]

Regardless of it's merits as a substrate.. I'm thinking that with my liquid rock water, STS seems to be working miracles with my PH and KH. It doesn't seem to be doing squat for GH tho.

Comparing a tank with sand, a tank with gravel, and a STS tank.

ph without StS 8.0 with 6.4
KH without STS 19.0 with 2.0

but GH was dissapointing without 32 and with 40

I may try using it in a media bag on my rack system to pull that ph down, rather like an ion "sponge"... has anyone else run into this?

 

[Diana]

It won't do anything to lower the GH.

It removes carbonates, and this allows the pH to be pretty much anything. If you have peat moss, leaves or driftwood the pH will highly likely be on the acidic side of neutral.

I would do something to the water ahead of time, before you fill the tank, to remove the GH.

 

[Contrl]

Thanks, from the looks of it I'll have to start using some RO as hardness in the 40's just seems excessive.