I was wondering if I should leave the diffusers on all winter or not. The pond usually doesn't freeze for more than a week at a time. It has already snowed three times but I don't know what the current water temps are. There is alot of leaves in the pond from the surrounding trees. I've got redear sunfish in the pond and I understand that they don't tolorate cold that well. The diffusers are only 2 or 3 feet from the deepest part of the pond. Any input would be greatly appreciated.

Shut them down! Not only are you wasting electricity you will stress your fish. They need a relatively warmer layer near bottom as a thermal sanctuary. Maybe if you had heavy ice cover and deep persistant snow it may be advisable to set up a diffuser in a shallow end of the pond but I no longer even do that.

The first winter I had my pond I mixed the water column all winter. I had disease problems the following spring due to winter stress.

Now all I do is remove snow in strips to allow light to penetrate and allow the rooted plants and phytoplankton to produce oxygen, and my fish come out of winter in great shape.

Redears are even less tolerant of cold water than other species.

As far as your leaves there won't be much decompostion going on in cold water anyway so running the diffusers won't help break them down much this time of year.

Bill Cody?

Thanks for the advice Cecil.

1st year with an aerator for me and I started thinking about this problem as well. Measured temp yesterday .. 40 degrees throughout the water column! I shut the aerator off immediately hopefully no damage has been done. I suppose the ground beneath the pond will tend to warm the bottom layer of water over time.