I found some of the Pro Lab One Flush product. I found it at our local Mills Fleet Farm store. This is a farm store that has locations in Minnesota, Wisconsin, and I think the Dakotas. Don't know where else. I paid $8.95 for a package of 3 packets, each of which will treat 1500 gallons. I figured I needed 12 packets for my pond so I bought 4 packages, that's about $36 to treat the pond once. I think this is more reasonable than any pond store source. No offense to anyone out there who sells pond supplies but my experience is that some times the same products are marketed to pond owners that are marketed for other applications and what do you know the price goes up. Some of this can be explained by differences in overhead costs etc. but some of it is simply when someone thinks they have a captive customer. In one way I feel kinda bad trying to find a product cheaper from another supplier in a different industry when perhaps I should be supporting The Pond Guy and such. I usually figure that if I take up someones time getting advice I'll buy from them even if it costs more. I make myself feel better buying elsewhere by doing lots of research on my own and talking to folks on web sites like this. Then I figure I'm not screwing anyone out of a sale. I got that off my chest.