It may be undersized for 100 gallon community tank. The 304 is an older model, as now fluval is up to series 6 (306). You may want to look into the 406 rated up to 100 gallons. A lot of it depends on population and the number of filter media baskets.
I would give it a try since you own it.
Another thought, These can filters need the media changed every so often. Since yours may be undersized, the changes may need to happen sooner.