Collapsing Holding Tank
Just discovered that the vent fitting on my holding tank was too small for the hose. My boat is a 2011, so it looks like it came from the factory that way. Lots of sealant and the hose was compressed way too much due to the smaller diameter of the fitting. I suggest others take a look at the vent fitting. If it's too small it might contribute to the holding tank flexing too much or even collapsing when pumping out. I noticed the same thing on my fresh water tank vent fitting but since there is no need to pump it out, should not be a problem.