mcliffy....I asked a few pages back and never got a response.....How far off the water are your lights??
Sorry I missed that. I'd say they are about 4" off the water, although I've had them higher and haven't noticed much difference.
Maybe try lowering it, but on the opposite end, maybe you are getting some photoinhibition because those are a lot of really high PAR bulbs, especially overdriven. I would do 4 blue plus, 2 AB special, 1 fiji purple, and 1 uvl super actinic.