I recently posted about the air pumps we sourced from eBay. We just got the smaller one installed on a steel bracket we welded under the solar panels.

The air pump is inside of the little polycarbonate roof extension just to the left of the solar panels.

As mentioned before, the air pump is connected to a hose that is attached to a relatively large air stone (about 8″ diameter if I remember correctly) that is on the ground nearly to the bottom of the pond. (About 3m deep.) When the air pump is turned on, air is forced down into the pond and escapes in tiny bubbles through the air stone. Those bubbles then float up to the surface of the pond, both aerating the water as well as turning over the water in the pond. (Moving the water at the bottom of the pond up to have a chance at the surface.)

Here is a closer-up view of the pump and bubble column it is producing:

I’ve attached the pump to a manual DC switch. I may eventually put it on a timer, once I figure out how many hours per day I want to run it. It uses a bit more current than one of the water circulation pumps, but only slightly:

The big green switch is for the new air pump. I actually bought a sensor for attaching to an Arduino that measures the oxygen levels in the water, but I don’t have an easy way to go out into the middle of the pond and drop it down yet. More on that to come…