I would think, you could leave the pumps running, shut off the skimmer,turn off any fans on the tank, turn of the lights except for actinics. Then cover the tank with 2 bed Sheets, not quilts or comforters. Then set off the bombs, the sheets should protect against fall out. The mist off the bomb settles on the floor and when a flea comes in contact with it, it dies . I think, this is only an idea, try it at your own risk!!!. A safer thing is to use the flea raps that have a blue-green light and you turn it on at night, the fleas jump to he light and then fall back onto a sticky paper there for you to clean up in the morning. I have used the light thing before and it works, just not great though, but is perfectly safe.