Canister filter ??

[Coralgurl]

I left my canister filter (fluval 405) full of water but not running for the last week as I wasn't sure I was going to keep this tank running. The water level was low as i moved quite a bit when i transferred everything to my other tank. I did keep the power heads going, still snails, crabs and a couple of corals and lr. Now that we've decided to keep it going, I've filled the tank back up (was down about 1/3), I opened the canister and it does not smell good. I had just changed all the media and cleaned it 2 weeks ago, so my question is should I change everything again, or just give it a good cleaning?