I stupidly used one of those phophate filter pads on my tank not realizing they would leach aluminum oxide into the tank.
The leather corals are very sensitive to these aluminum oxide particles and I have gotten instructions to remove the aluminum by
a) using a poly filter pad (made by poly bio marine)
and
b) running a diatom filter
Those filters are hugely expensive though.
Do any of the fish stores rent equipment like that?