[Motor31]

Bill you can use the black tank flush hose fitting to do that. Time how long it takes to fill the 5 gallon bucket from the hose then double that time flowing water into the black tank with the dump valve closed. That should add between 5 to 10 gallons into the tank.

When I dump I close the black tank valve and let the water flow into the tank for at least 15 to 30 seconds depending on water pressure to add water to the tank before use. So far it has worked well to help keep the tank dumping freely at the end of the week. Since we full time we dump every 7 to 8 days and ignore the tank sensors. They were accurate only for the first 2 or 3 weeks we had the trailer.