Hello, I am new to saltwater tanks. I have a 40 gallon with 30 lbs of live rock and 20 lbs of live sand. I also have 2 power heads which alternate in current. I also have a hob filter. My tank has been running for about 5-6 weeks. I have 3 chromis, 1 clown, 5 hermit crabs, and 2 sand snails. I...