newbie

[08arcticcat]

I have a 40 gallon tank that has been cycling for almost 3 months. It has roughly 2" of sand in it, and 40lbs of dry rock. I tried getting a cycle started by ghost feeding the tank with some fish food. whenever i checked the water, all parameters were good. good pH, 0 ammonia, 0 nitrates, 0 nitrites. so after enough waiting and multiple tests of 0's, i decided to buy some hermit crabs and some emerald crabs.

I have zero growth of anything in my tank, not an ounce of algae or anything. My question is, should i do something to get some algae growth for the crabs or what should i do to feed the crabs??