I've run my Vertex system non-stop from the day the water started going in the pond and it does a great job at turning the entire pond over at least once a day. Pond is 7' deep at the center (bowl-ish shape). The forecast is calling for lows in the 20's the next 5 days starting Monday morning. I checked my water temp today (about 12-18" below surface) and it was 56 degrees. The only fish in the pond are FHM/RR, RES, and CNBG (and maybe a couple goldfish tossed in from the galvanized stock tank).

My question is, should I shut off the aeration until temps come back up or leave it running? I don't really have a concept of whether a week of hard freezing temps at night would drop the water temp to a "dangerous" level if it's continually circulating or not... just looking for some advice.

/c

When your fall-winter air temps are below 55F & decreasing and water temps are on a decreasing trend the pond will daily mix top to bottom naturally due to wind action and nightly convection currents. In spring the opposite is true. Increasing air and water temps (60-70F+) tend to promote the development of the top warm water layer. Then mechanical mixing is important if one wants to avoid thermal stratification.