I run AB plus also. Depends on tank size of course but mine is 36x24x22 and with 2 XR15 pros at 38% corals are fine and sand 85% white again. When I ran higher intensity that's when the sand got dirty looked like a mixture of diatoms, cyano and maybe even dinos for awhile. Rocks not to bad just the bottom sand.Im running a modified ab+ and 100% so its quite the difference there