My experience? Whenever I have had algea problems..I have always had a phosphate reading. Once I took care of the phosphate, the algea went away. I also have lots of snails, a couple urchins, a yellow tang that love to pick away at certain types of algea, crabs, blah, blah blah..I am sure you have heard it all. One thing other then enviromental issues to control the algea on the glass....I was VERY greatfull when I purchased a magnet that I can leave in the tank..I can tell you the company name. It wasnt cheap, but it sure beat dunking my arms in the tank every day...besides, many time there is soap residue or other household products that may be on your arms and may fowl your water.