i have a 70 ltr tank, it has two filters running and 15-18 small fish.i had a small algae problem nothing major so I removed everything cleaned tank and hoovered tank. I have been told to cover tank during the day to prevent algae growth, someone who I would assume has good experience with aquariums has told me there is no point covering tank if there is direct sunlight coming into the room and hat the algae will still grow. What are your opinions? I would have assumed if the tank was covered during the day it would not matter if light was coming into the room.