I have a 10 gallon tank divided 3 ways and I do a 50% water change once a week. I try my best to get around all the ornaments and get all the poop and leftover food. No matter what though I get greenish brown algae on some of the decorations and on the tank walls. I also get condensation builldup above the water line. I scrub the walls every week with a toothbrush but it keeps coming back. I know it's nothing harmful but everyone who sees my tank thinks it's filthy. And it LOOKS dirty even though it's not. Would it be worth it take out my fish and completely strip the whole aquarium and completely clean everything, gravel and all? Or is there another way? Or should I leave it the way it is...water stains, algae and all?