So, do you think there'd be some danger from increasing the K level a bit? No fertilizer has been added to the pond. I assume that the fish and food waste have added some nitrogen, but no algae so far. My "plan" was to broadcast 3 or 4 5-gallon buckets from the shoreline.

I tend to think of wood ashes as pretty innocuous. I usually spread them around the garden- mainly on asparagus and daffodils and cole crops.

In a bucket of water, they settle out in an hour or so leaving clear water that I assume is pretty alkaline.

BTW, 1/2 ton of ag lime (2 tons/acre rate) was spread around the bottom before the pond filled last summer.