Crushed Oyster Shell 500g

Crushed oyster shell is essential for raising the water hardness in aquariums. It helps to maintain a stable KH which in turn helps to keep a stable pH.

The shell grit may be use 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 a nylon bag so it can be removed once the level required is achieved.