Here is an interesting point that Donnie told me on the phone. The DO was the same at the far end from the diffuser as it was directly on top of the diffuser boil.The DO was evenly consumed The water is very green and clarity low and recent hazy hot days > these are text book conitions for this situation so be prepared. Donnie thanks for taking the time to post as I believe you may have saved many more fish for others from your experience.