Well, bad news and good news. The good news is, the areas cleared by the current have stayed pretty much clear of chara even with the summer explosion. The bad news is that somehow the chara fought back. In an unknown order of events (while I was away on vacation, of course) the chara clogged the prop, the prop unscrewed itself, and the cable near the prop was lacerated. Not sure how all those things happened but they sure did happen. I have sent it back to the seller to be repaired but in the mean time I am getting very tempted to resort to herbicides as the duckweed and chara really liked the grass fertilizer that just had to be put on the lawn.
I guess ya win some, ya lose some

0.7 acre pond stocked 2020, LMB, PS, YP.