hey flo, I've got a 750 gph air pump that runs 3 med round stones in the cooler and 3 in buckets (yuck). That cooler cost me like 150 bux to put together and I'm thinking its gonna be money well spent. I'd like to thank boomer for the idea, I looked at his set up and realized I definetly needed to do similar, not exact copy of course( he doesn't show his internals!) so....thanks boomer, I know you didn't invent the concept but you're still alright by me! So, the cooler has 8 sprayers and a 400 gph water pump and I had such a headache already from building it I blew the filter off, there wasn't much space either, height that is, so I couldn't get a filter inline and I might pay for that in the long run by replacing a lot of sprayers. Thanks for the +rep flo and right back to you!