[BB_TX]

Impressive setup. I followed a far less scientific method. A dual shutoff Y valve at the park faucet, one hose to fresh water and one hose to black tank flush. When draining the black tank I would drain the tank, when drained close the valve, open the water to the flush input for 1 - 1 1/2 minutes, open tank drain valve with flush still running and watch for solids passing thru my clear sewer extension, close the drain valve for another 1 - 1 1/2 minutes, open drain valve and watch for solids, maybe repeat again if any significant solids seen, close drain valve for another minute or so to get some water in the black tank. Worked fine for 14 years with no issues. Cost? What ever that Y valve cost; $5 maybe???.