I have a problem with gnats in my tanks. I am using Eco-earth (which I've heard sometimes attracts gnats)and I have changed it with the gnats returning soon after. They are annoying to my frogs and toads (and us as well-we've even had some upstairs). They don't hurt the guys, they just land on them and fly around them.
Any thing I can do to get rid of them? I've hung fly traps closeby and they just fill up with no noticeable change in gnat population. Is there some sort of environmentally-safe product I can use that won't hurt my frogs, or should I just keep swatting?

