That sounds like why they are so cheap. I am going to do some out of pond water tests first and maybe post some pictures or if i can figure out how to post video we can see the performance. I am gonna pull the trigger on a Gast 82R45 today with a powder coated cabinet and cooling fans already installed for 200$. I hope to see everything hooked up next week. I assume since that membrane has larger holes my pump will probably be too small but we will see. I am at an average depth of 5' and i plan to hook up two diffusers right next to each other at my deepest point of 8'-10'. i was thinking of putting the third on the opposite side of the small island i have but i will have to do some testing to find out how it all looks. My pond is pretty small and it should be enough water turn over, but i guess if could get smaller bubbles i might run my pump less. I found some 12'' diffusers for 34$ i wonder what there hole size is?
