first off is your tank still cycling? if so what size tank, and how much live rock
are you using RO/DI water or tap water?
How much flow and light do you have on the tank?
Algae is not good for the tank, if the tank is still cycling than you can kill it off and use water changes to pull out the nitrates, also if you are cycling, than your fish might die, they dont do good with ammonia as it burns them
as for the red stuff does it come off if you rub it with your finger? if not it could be coraline algae which is good