Never completely clean out and disinfect the gravel as it holds a ton of good bacteria for the tank. As does the filter, so its best to change the filter a few days before a water change to retain as much good bacteria as possible.

I would just recommend doing water changes once a week taking about 2 gallons of water out from your ten gallon with your gravel vacuum. If you have a ton of gunk on the bottom, your obviously overfeeding your fish, so i would cut back on the feeding and start maintaining the tank more often. The biggest think with freshwater tanks is being consistent and cleaning the tank on a schedule so the oxygen gets refreshed and your fish don't suffocate.