We are full-timers. A year ago we did some volunteer work at a non-profit that had a large septic system. We started seeing little black bugs coming out of the black tank when we flushed. They kind of hop around, I think the way a flea might. We asked the owners about this and no one knew anything about it. Eventually they agreed to open the cover in one area of the septic system and a huge cloud of these black bugs came out. To make a long story a little shorter, we occasionally still see these bugs. We might go for several weeks without seeing them, then they again appear. We do, of course, use chemicals in our black tank and do not have any odor problems. It seems that these bugs must lay eggs in the black tank and they eventually hatch. We have sprayed all kinds of bug spray down the toilet. We have tried using clorox and filling up the tank with water to clean it out, etc. but we still see them. We've thought about somehow using a "flea" bomb in the tank, but the box that the bombs come in always say not to use in a room less than 5' x 5'. Anyway, you can see we're getting kind of desperate about getting rid of these things. If anyone has experienced this type of situation we'd be especially happy to hear how you "eradicated" them. Thanks for your help.