A while ago in a different thread (can't find it, unfortunately) I read that when you're battling a bacteria bloom you have to do daily or twice daily water changes from the top of the tank to clear it out. Don't vacuum the gravel, just take the water from as close to the top as you can. I can't say I understand why this would work, but the person who suggested it said they cleared their bacteria bloom in a few days with this method, if I remember right. It couldn't hurt if you're out of things to try.