first IMO i would get rid of the charcoal and go with live rock rubble, but bio balls will do.
2nd cut back on ur feeding a little bit and test ur nitrates everyday.
3rd have you checked your phosphates?
you can use a phosphate sponge for slower removal of phosphates or you can buy a filter sock and some "phosguard" and reduce nitrates to almost 0 overnight.
Many people forget about the phosphates although your nitrates are high i would suspect that both nitarates and phosphates are out of wack mainly because you lost inverts and that's a phosphate problem almost for sure.