Thanks for the feedback guys.
Bill, there is a sump pump check valve at the bucket connection. I don't understand how a big bubble working its way through pea gravel will coalesce. Intuition makes me think that a bubble will divide on its way up. Does it reform at the top?
Also, with very fine bubbles I believe there is significant transfer of O2 into the water. I found this neat article that discusses some science around that topic.
http://www.ksn.bio.aau.dk/Semestersider/Aalborg/K8/k8m/WWT/WWT3b.pdfBing, I have heard the same thing about under aerating and have done a lot of reading on the topic. I also read Sue's post earlier about under aerating. It also included a section about successfully aerating a single cove in a large lake. We had our disaster last year with a major fish kill at the end of a hot summer, followed by many cloudy days, causing an algae bloom crash. The lake contained about 20 grass carp which all died. Nothing over 4 or 5 inches survived. I always wondered how effective the grass carp where, we found out this summer when weeds/grass took over the lake. Eight new grass carp are scheduled to go in next spring. Chemicals have been applied this summer which has caused a weed/grass crash, similar to the algae. The past 2 or 3 days have been cloudy here in Cleveland which was apparently was enough to drop the O2 because fish were gulping at the surface this morning. We have had a larger system spec’d out, but the cost was an issue. Our lake is over 5 acres, oddly shaped, and shallow in a significant portion. I'm hoping the aerator will at least create a zone of survivable O2 similar to the cove Sue described. If it does we may add a couple more.
