Theo, sounds like you are on track, When the zero temps return and you have an open area consider letting it freeze clear and bypassing by venting the air off. In these cold temps depending on the size of the pond you are probably still pulling warmer water temps from the deeper areas (1 acre or less is just a guess)and DO shouldnt be a problem.Ice cover is such great insulation.
In small ponds open water and over circulation can be more of a problem than low DO.I am going to monitor DO in my small pond (now has a 5 ft opening)with a 20 ft snow off area. Once it is snow covered again I will see if I can go 2-3-4 weeks or longer without clear ice and still keep the DO at 6ppm plus.
If open water in 1 acre plus ponds I don't think the 7 inch standard airstone and the windmill can over-circulate. EVERYONE keep in mind if starting up a shallow (or any depth) winter diffuser that the air will "trail off"under the ice possibly hundreds of feet away and cause potentially dangerous thin ice until a hole above the diffuser is in the ice. So thin ice can be hundreds of feet away and normally you will have thin ice at the shoreline (listen for the air escape) before you have open water.Also since many of todays aeration systems run very quietly or are located hundreds or thousands of feet away be sure the power can not accidentally be turned on, Even a system with a low circulation rate can cause thin ice in a day or two and the ice always looks the same thick or thin.
Last edited by Bill Cody; 01/19/20 05:22 PM. Reason: fixes
