I used the sponges for months, but recently took them out. My water seems to be doing better, but I did a bunch of things so not sure that mattered. One less thing to clean, though.
I run two chemi pure elite, a purigen, and right now phosnet (which is probably overkill) as well as some filter floss.
Anyway, sharp looking tank and cool coral selection. Good to see it clicking along.