Why can't I fill black tank with tank rinse on the hose?

[RV Vagabond]

What do you think about draining the gray water into big jugs and flushing it down the toilet to help clean out the black system

[Scatterbrain]

Originally Posted by RV Vagabond

What do you think about draining the gray water into big jugs and flushing it down the toilet to help clean out the black system

Drain the black tank first, then leave the valve open to the black tank and open the grey tank. The water will flood into the black tank, helping to pull out left behind solids. After both are empty close the valves and fill the black tank via the flush. Drain and fill again, or until water comes out clean and clear.

[scottandanna]

Originally Posted by RV Vagabond

What do you think about draining the gray water into big jugs and flushing it down the toilet to help clean out the black system

Black tank is clean now. Before the trip, I drained it empty, and put half a gallon of bleach down the toilet, and continued to flush it until only clear chlorine water came out.

The issue since is if the water pressure is too high, it blows past the one-way valve under the bathroom sink, leaving a puddle of water after flushing the black tank.

So today, I removed that valve, and instead, used a brass back-flow protection fitting on the outside of the trailer between the freshwater hose and the black tank flush connection.

Now, I can flush under high pressure, and no dripping onto the floor.

Tank is clean. After about 5 minutes of running the black tank flush, water runs clear through the sewer hose.