When filling with water, most of it dumps out the side.

Due to poor design I have to feed my fresh water tank slowly or, like yours, fresh water is forced out around the hose. To add to this bad design my tank feeds from the side so you can never reach intended tank capacity. Soon as a left hand turn is made water comes out the fill inlet. I put a short piece of hose with no male end on my fill hose. This takes the water outlet into the tank so air can more easily escape. Helps but does not cure