howdy abadtrip, That is why I use separated DWC reservoirs without all of the interconnecting plumbing. I have found that if it cannot be boiled or soaked in a strong bleach solution for cleaning, then it gets tossed out. Replacing a $10 water pump, a $6 distributor, and two $2 air stones is a small price to pay for a clean system. I tried, in the past, to sterilize the air stone in H2O2, but that did not work, and they can not be soaked in bleach because it will 'leach' out into the new grow. I clean out the reservoirs with first, a 50% white vinegar and water solution overnight, then wash out with soap (anti-bacterial) and water, then leave them soaking filled with a 25% bleach solution over night. The reason that I use the vinegar solution is to remove and leftover nutrient salt residue that has been deposited on the surface of the reservoir. I have had a granular 'coating' on the bottom a side of the reservoirs after cleaning and drying before, the vinegar dissolves this away.