does live rock disinegrate over time?

[bws]

I have some rock that is probably 10 years old or more, its been swapped around from a few different tanks over the years. Recently I have been noticing little crumb looking things on the Hawaiian black sand I changed too. I am wondering if this is stuff falling off the rocks like the structure of the rocks is falling apart they seem fine when I touch them though, another thing I wondered if what I am seeing is the end result of sea urchins chowing down and never noticed it with the normal white sand

 

[ca1ore]

Absolutely it will disintigrate over time. Erosion from water flow, scouring from urchins, picking at by fish. Whether said erosion is material over the lifetime of any given tank is a different question.

 

[VWD]

It will over time like Simon said. I have found the lighter and more porous rock to do it at a faster rate.

 

[SoloGarth]

I find my live rock grows over time. It is interesting to see the process take place. There is one spot where a large spongodes colony battles a large lobophylia. There are approximately 5 layers of dead spongodes built up there. As long as there are corals encrusting on the rock is shouldn't disintegrate. HAha.