Thanks,

The windmill is an aerator but it doesn't work at the moment. I need to check the diaphragm I guess.

The only thing pulled out of the pond so far is what folks call google eyes. Most have been no more than 3-4 inches. here is the best one taken so far.

Eventually I'd like to have the pond as a source of eating fish maybe tilapia (just not catfish.)

I'd like it to be clean enough to be comfortable going for a swim but I'm not sure how realistic that is.