I have been running one of these over a 30 gallon rectangle for a couple of months and can't seem to find the happy medium to keep all of the corals happy. I have it mounted on the light to tank bars that it came with so it is approximately 8" above the water. Does anyone have a similar set up and know what a good daytime setting is for proper par saturation? I have sps in the top half of the tank and zoas, softy, euphyllia in the lower 1/4 to the sand bed. a PAR meter would of course be the answer but I can't bring myself to spend that much money on a device I would very rarely use.