[64Ivy]

My tank will be 10 next year, 7 as "SPS" dominant, and I don't see any signs of OTS. It has always been barebottomed and it has always been aggressively skimmed. I use a kalkwasser doser as a topoff and about 4 years ago, I added a macroalgae refugium to help with nutrient export. Once or twice a month, I'll go into the tank with a hose attached to my sump pump and really blast between and behind the rockwork. You'd be surprised how much stuff gets blown into suspension.

I suppose if it's true that sandbeds eventually get 'full' and begin to leach out phosphates, etc. then I guess it stands to reason that live rock eventually does too. But I'm an NOT about to tear down a 500g tank every few years so what I do is keep extra LR in my sump and THIS is what I'll change every so often. Also, when fragging out corals, I'll find myself replacing LR from time to time. So far, it seems like this is enough.