I'm no expert but I've tried 3 single reflectors. Coralvue (came with the fixture) Aquactinics and Ice cap. The Coralvue were OK but they had plastic clips that broke after a couple bulb changes. I never tested the PAR but they didn't appear to be as "bright" as the other 2 to the naked eye. The Aquactinics and Ice Cap looked the same to the naked eye but when I was running T5's space was at a premium and the Aquactinics were 2" wide compared to the Ice Cap at 2.5" so I ended up using them over the I.C's.