Not sure on the white rocks myself.
It's about time! Not loving the rocks either. The only time I ever really saw wood work well with rocks was in a river bed type biotope where the rocks were rounded and smooth and didn't contrast much with the substrate. A question, you still have the 4x54 t5s in this tank? If so, I agree with George and advise more bps as well. Remember, though you have less than 2WPG, this is a 110g tank and 1.96WPG is going to probably be high light in this size tank. You really don't have a lot of plantload in this tank. Are there any stemplants? I think I see a few crammed in the back, but not at the numbers I expected.
llj