We put our pool up July 4th and have caught 100+ in the skimmer. My son makes a game of it with goggles and a net. The other I rattled the ladder and out they came. 1huge one and a bunch of liitle ones. They were immediately caught in the net and exterminated with extreme prejudice. We've had the solar cover on for a couple days. I hate to see what's living in there now.