looking for a source of calcium carbonate

[Pete Schuhmann]

I am trying to find something to raise my ph levels. I have found a poultry supplement made from oyster shells. It is ground to a small size but not to powder. Has anyone used this before and will it work not being in powder form?

[RupertofOZ]

It would certainly work.. as does "shell grit".. as fed to chocks... but it's a kind of "slow release"...

If you need a faster acting compound.... get some Hydrated Lime... often called "brickies lime".... and/or some Potassium BiCarbonate (brewing shops)... alternate between the buffers..