Find your balance point empty. Usually between the two axles. Move 225 lbs or so, weight of water and tank and hose etc back and forward and observe measurements to bottom of frame of RV on a hard level surface, on both ends. Probably the existing tank is near center. Maybe replace it with one larger one with plenty of baffling. check it with weight of your toys too. May want to think about weight distribution of load of toys and where weight, of extra water and existing water etc sits. Don't want the tongue diving or rising on the towing vehicle. Should sit level.
