How do you clean a tank?
when you clean a fish tank you should only do a 5 or 10% water
change. You should wipe any algae off the glass, filter of objects
in the tank using a new cloth as any soaps that get in the
water will kill the fish. After this the water may be cloudy but
the filter should clear this within a few hours. You should
never do a 100% water change as this much change will overwhelm the
fish and could kill them.