[twindman]

I see no need for a Flush King or anything like this. The Black tank has a backflush system that is probably better than the flush king. The water goes directly into the black tank. I alway drain, close valve, run the backflush for 5 minutes and dump again. If it wasn't pretty clean water, I repeat this. I figure I can't overflow the tank because that would be over 8 gallons per minute, or 1 gallon in 7.5 seconds. No hose is that fast.