Stephen, Watermeal feels like a gritty sand if you get some in your hand. From the distant picture, it looks like an algae to me with the swirling spread.

In Dubuque, I would say 7-8' depth causes annual winter kills. 10-12' would be much safer, and only if you keep snow cleared off at least 20% of the ice.

I'd suggest using a piece of 3/8" rebar to measure muck depth. 4" PVC can't cut through all the leaf litter that has to be there with all the trees surrounding the pond, and from a 30+ year build-up.

I would venture to guess muck is only 4-5" in 3 feet of water or less, and 3-5' deep in the deepest areas.

As was mentioned on using a water pump, do that for aesthetics. Pumping water only moves a fraction of the water volume tiny air bubbles can lift...air is a fraction of the electric cost also.

That is a gorgeous setting and well worth investing time, money and effort into!!!

Last edited by Rainman; 02/19/16 12:22 PM.