Helps to raise KH levels which may also increase pH levels or stabilize them

Crushed oyster shell is used for raising the water hardness in aquariums.

The shell grit may be used in aquariums over short or long periods to alter the hardness to a level where a buffer can be used.

It is advisable in fresh water aquariums to place the grit in such a way as it may be easily removed once the level required is achieved.