My pond is about 8500 sq ft when full with an average depth of 6 or 7 feet with a max depth of 12.5 feet. That works out to about 400K gallons give or take. At the moment I'm about 1 foot over the drain and it's dropping fast since the rain stopped.
I've got a dual rocker piston setup that I installed a few weeks ago that puts out 3.2 CFM @ 35 PSI. At depth it's a bit less than that, but not a lot.
I currently have 1 diffuser in the deep end at ~11' and the other at the shallow end at ~6' or so. With both ring diffusers more or less wide open the pressure reads about 13 PSI according to the gauge and there's a significant amount of boil. If I open one of the spare valves to lower overall pressure to 5 PSI the up-welling slows to a more sedate flow but the outflow area is still a good 20' wide.
The vendor has no idea what the diffuser lift rates are but if I assume (I know, I know) a combined lift of 3000 GPM at the lower pressure the system would cycle the total pond volume in about 2.5 hours. As a test I added some pond dye yesterday with the higher pressure and the dye was fully mixed in about an hour.
When I took temperature readings a while ago there was less than 1 degree difference top to bottom after 4 hours with the pond down about 5 feet so I know it fully mixes. I just changed things to run 6 hours now that it's full, but at the lower flow rate.
Based on what I've read I know it's not good if the total volume isn't moved in at least a day. The question I haven't seen an answer to is if one ignores the cost is there a down side to cycling at a (significantly) higher rate?
