I have recently set up a 200L saltwater tank (~4 weeks ago) and i have had live rock and sand in there ~2-3 weeks now. There is now brown algae growing all over my live rock and even on the sand and glass of the tank! Is this a normal phase of the tank cycling? Is there a clean-up crew i can put in there now to help with the algae issue? Hermit crabs/snails? I am hesitant to put the lights on in the tank now but know that the rest of the stuff growing on the live rock needs the light. What should i do?