Brian, I'd have to think in your current drought climate temps, at .1 inch addition, you are only reducing daily loss from evaporation to about 1.4" per day. I would assume you are just tapping into energy already being consumed, but I would put the highest flow jet nozzle and place the stream low and flat on the topia surface hoping to get some minor circulation started and minimize the aerating because there is a faster evap rate on the same surface area that adds DO. You have a low biomass right now, so LOW DO should not be a concern with the low volume of well water. I don't know how much more volume of flow lowering total head pressure might gain you here, but max flow fresh water and more of it would be better even without creating a circulation, IMO...an added benefit might also be slightly cooler water temps as a result of the idea suggested.
