Bill, you are correct. I need to test the EasyPro diffuser since we are a distributor for both Vertex and EasyPro. I tested a single Vertex diffuser a number of years ago and it had no issues running for 4 months in 4' water depth during the winter when using a Gast 1023 3/4 hp rotary vane compressor. It was WAY over cfm Vertex specs. IIRC the back pressure tested like you described was 1 psi. It takes 0.5 psi to open the check valve in the Vertex diffusers.

I tell my customers that they could turn off the system when the water temp is in the low 50's and dropping and that they can turn the system back on in the Spring when it's in the upper 40's to low 50's without worrying about the start up procedure. I tell them to turn the air on going to the winter diffuser when there is or will be 2" ice and 2" snow on the pond. Some years it's on for only a week or two. Last winter it was on for about 3 months.

That is WATER Temperature, NOT air temperature. I take water temp at 12"-18" depth.

When my pond lost 9 foot of water depth due to a drought, (half the pond depth) I took out roughly 100# of fish before the pond iced over, and re-configured both the shallow and deep airstations so they'd BOTH work for the like they were supposed to. I had probably 30% of the surface area ice-free and didn't lose any fish. BUT I was concerned because of the high biochemical demand on the pond that winter.

Now what I do for my customers that have ponds that ice over, I found a diffusers that has medium sized bubbles for the winter diffuser. Larger bubbles make more surface disruption (waves) and open up a larger hole. This one uses 2-12 CFM, and has 6-10mm bubbles. Compressor specs are important, a low cfm compressor won't work with these diffusers.


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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).