John:

I have 2 small stock tanks near the house that I'm using as small ornamental ponds. One is 300 gallons, the other is 100 gallons. Both are sunk into the ground and are heated during the winter to keep them from freezing solid. They both normally have a thick photoplankton bloom, visibility varies from 6" to a foot, but it usually runs around the 6" mark. Over the years I've had FHM, Gambusia, a couple of PS, GSH and lately Blue Tilapia. All monocultures. Fish density has varied from very heavy to only 2 fish in each tank. Less fish = better visibility. But, in all cases, I have never had a FA problem in the tanks. The larger tank has a submerged filter, that has filter mesh and bio balls in it. It doesn't seem to matter if it's run or not, the visibility stays the same.

I don't attribute the lack of FA to the fish in the tank, rather I attribute it to the thick bloom that limits sunlight.

One year I had FA start in the early Spring, but as soon as the bloom started, no more FA. That was the year that I had PS in the tanks, and the water was exceptionally clear that Spring, I could see the bottom of the tanks for almost a month straight. I'm sure the PS didn't eat the FA. There are no plants in either pond.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).