I've had my 55 gal community tank set up for a little less than a year. I wanted tips on what to use for cleaning the gunk around the canopies, mostly around the filter(AC 300), and mabey preventative tips (if there is any) to cut down on the gunk type stuff.
I'm not sure what kind of gunk you're referring to near the canopy. Dried crusty stuff? Personally I leave it until I can flake it off with a hammer and chisel . As far as gunk and sludge in the filter itself, I bleach it. Remove the filter and let the sponge and media sit in a bowl of tank water unbleached. Rinse it well in tank water to keep from killing the bacteria in it.
The body of the filter, the tubes, impeller, etc... all go in a 20% bleach soak for a couple hours. Rinse well, very well. It's only chlorine so if you're concerned about it, you can add some dechlorinator (the cheapest stuff you can find) to some clean non-bleach soak water for a couple minutes, but it's not necessary if you rinse well.
Once a month or so, I just unplug the filter (leaving the fiter cartridge) and clean all the tubing and intake with a toothbrush. I alternate and don't change the cartridge if I am cleaning the tubes, etc. You would be amazed at all the stuff that you will clean out...most of it just looks like beige goop...
I don't soak either item, but maybe I am old fashioned and just like to manually clean things up???
Weekly Water changes as a minimum 40-50%. Rinse the filter cartriges out in tank water once a month, VERY good, get as much as you can off it. I don't clean the mechanical portions of the filter other than the impeller area. The stuff on the lights, I remove the canopys and take a cleaning solution and wipe it off, may need a razorblade sometimes, but be VERY careful with it.