i clean my glass every 3-4 days, gets a light film of green-brown slime. this is normal, if you have enough light for corals then you have enough light for algae. feeding your fish isn't the problem unless you are feeding way to much. its the waste coming from the fish that is more the issue. that is more of a food source for the algae. but the algae is also a food source for your fish and snails. what you want to do is hopefully have it balance out. feed the fish, they poop and that feeds the algae, fish and snails eat the algae, you clean the glass, the dust coming off the glass feeds the corals, etc. i know its not dust but thats what it looks like and its a good food source for your corals. keep your filtration and skimmer clean, do water changes to keep it under control and everything just keeps rolling along. the only way that i know of to stop algae completely is to keep your tank in the dark and even then you get this brown scum on everything. if you are getting an excessive amount of hair and bubble algae then cut way back on food. more food for the fish more shit in the water more food for the algae.