sulphur reducing bacteria

[kirkufp]

I had a breach in my well and my 150 g tank has become infected with a white and grey slime wich is either a sulphur reducing bacteria or a sulphur oxidizing bacteria. I have now torn down my tank twice and bleached everything for a 24 hour period. Using City water to refill the tank. This stuff takes over quickly and outperforms benificial bacteria causing ammonia to rise and ph to drop. My local Fish store has bee providing me with filter media to keep my cylcle down to a min but what can I do to rid myself of this bacteria. 155 bow front, freshwater, wet dry, 8 changes per hour, canisterfilter. Any help would be appreciated.