<a href=showthread.php?s=&postid=7853315#post7853315 target=_blank>Originally posted</a> by ChinChek787
Phosphate will bind to the sand, eventually the sand will no longer be able to bind phosphate and it will begin to build up. I would think that simply removing the top half would be adequate as it would leave a good protion of the denitrifying bacteria in tack while providing fresh substrate for nitrifying bacteria on more phosphate binding. A phosphate reactor would help prolong the usefulness of the sand.
Probably a good idea since the aragonite can release the phosphate fairly easily:
http://www.rsmas.miami.edu/groups/jmc/fla-bay/fbay.html
http://www.advancedaquarist.com/issues/sept2002/chem.htm