All you need to replace your filter cartridge and maintain your marine biOrb.
The kit contains a replacement filter cartridge which is specifically for Marine biOrb (the biOrb Standard Service Kit should not be used in Marine biOrb as it contains a different mix of chemicals).
A measured amount of high quality reef grade salt and water preparation chemicals are also supplied as well as easy to follow step by step instructions. The filter cartridge in your biOrb should be changed regularly. Frequency of filter changes depends on the size of your biOrb and the fish stocking level.