Press chiller system needs rust inhibitors and glycol if its a closed system, press fountain system can be cleaned with bleach. flush system with warm water and mild bleach liquid. Make sure system has been flushed again with clean water before filling with fountain solution chemistry
Most modern fountain solutions have an algicide mixed into their formula. If its not enough, you might ask the manufacturer to either mix you a special batch with more in it, or get suggestions from them as to what to use.