I agree if you can seal the crack it will be fine as far as filters when I ran filters about once a month I would take the pads out amd rinse in FW and then replace with no ill effects.
have you modified the skilter for better skimming??
if not its easy to do and makes the skimmer a decent skimmer.
take the top cover and drill a whole big enough for an airline tubing to go through and place a fine airstone on the chamber attach to an airpump and disconect the original airsupply and your done turn it on and see what nasty stuff it pulls out, LOL
HTH
Mike