Black tank building pressure
Iíve noticed when Iím flushing my black tank it builds up pressure. I empty the tank then close the valve and add water with the flush. I usually go inside after a few minutes to check the level. I turned the water off and I went inside to check the level and I heard air or water escaping. I opened the toiled to check and boom, water all over. Isnít the vent supposed to prevent that from happening ? I know some people say to leave the valve open while flushing but I want to make sure everything comes out of the tank so I fill it a few times to make sure itís clean. Anyone know whatís going on ?