Pond Boss Forums AERATION Systems questions DIY Pond Deicer vs Aeration

The hole he has open will not do any good(extremely little good) in my opinion.

You need water to air interaction to see the benefits. Keeping his hole under a lid defeats the purpose of having a hole open. Also, that size hole is of very limited use.

Do it right, or don't bother.

That said, there are more efficient ways to keep a hole open during the winter. A small air pump with a single defuser can do a lot more good than most think. Start out small and add if you must. Understand your pond. Its location, the temps you will see and for how long, how much sun do you get, location, location, location, ect.

Moving air is the cheepest way.