That pump appears to be a Stratus ERP Series single piston which has an open flow of 3.5 cfm and at 5 psi backpressure is in the 3.1 cfm range. You have a "lot" of air for two diffusers. 1.5 cfm would of been enough.The punch on your discs may be medium which even for that size bubble will create a lot of turbulance.That blue aluminum manifold may have a threaded .375 plug in the end. I would put a 90 degree elbow in that and put the brass relief valve there and then add another valve between the two you have to act as a bypass. The bypass will be loud and you can just add another hose to it and submerge it in the pond to quiet it down.I think running it just now and then will resuspend things. I would consider just slowing the system down as mentioned. Also note that the water is now moving up to the unrocked shoreline and you may be pulling some clay back into the water column. As far as the lifting rates this is something your dealer should be able to tell you when you state the depth of each diffuser to them.For example you may have one stsion at 7 ft and have 1.55 cfm going to it and that lifting rate "could" be 1500 gpm ( just a WAG) then with the other one calculated you may have 2500 GPM total which equates to 3.6 million gallon per 24 hr day. If your pond is 1/4 acre at 5 ft average it has approx 418,750 gallon so you may have 8.597 turns per day which is a lot for your goal. So the math would say for .8597 turns per day run it just 2.4 hours per day but it wont work that way. You may need to lift less per minute but do it over a longer period. Hope this makes sense as I know it can be confusing. Bottomline, You are probably overcirculating from what youve shown me.