Freshwater invertebrate calcium level

[farrell989]

What is considered to be a good ppm of calcium for shrimp, crayfish, and snails? 

[Wes L.]

I've never heard of anyone just singling out calcium....except for salt water tanks. Invertebrates need both a decent level of calcium and magnesium. The magnesium keeps the calcium in a dissolved state, and that keeps the calcium readily available. Not much use having a ton of calcium in a tank if the inverts can't absorb it. The good news is calcium and magnesium together is the General Hardness of a tank. So as long as your general hardness is over 143.2ppm (8dGH)  you should be good. HOWEVER, the type of shrimp you have will also determine a proper GH level for them. Different shrimp do well in different water conditions. A great source to check is www.theshrimpfarm.com. They list many different types of shrimp and the water parameters their shrimp are kept at, as well as an acceptable range of water parameters that the different species of shrimp will thrive in.