Been using it for as long as I can remember myself and have yet to
have aproblem. Just do not get it after a heavy rain, or in areas
there is a heap of run off or where storm drains empty into the ocean
at. Same for the sand. I find the silica baed (Quartz) is as effective
in a marine tank as the high dollar aragonite. I just do not buy that
crap about aragonite being needed to help stabilize the ph or for
certain sand sifting critters..None of mine have complained.