[C320-list] Holding Tank Flooding

[Kaare Wold]

Skippers,  Recently we noticed that our holding tank fills with water when 
at rest at the dock.  At first, thought our dock attendants failed to pump 
out.  We have an AccuGage digital monitor on all tanks.  Love that setup! 
We had the tank pumped, while we were present,  and as the tank was being 
pumped out, I could see the AccuGage digital level drop from 3/4 to 1/2 down 
to empty. A couple days later, it was back to 3/4 full without any personal 
use whatsoever.  The macerator thruhull had been open all the time, although 
we never use that device.  All thruhull are opened for winter layup and I 
never closed it after spring launch.  I now closed the thruhull, had the 
tank pumped out again and.....bingo...,  the tank remained empty.  Any ideas 
from our knowledgeable group???   Could there be a check valve in the 
macerator pump that is leaking?    Looking for some suggestions or comments 
from someone that may have experienced the same problem.  Thanks to all for 
your comments.
Kaare & Mary Wold
Sheet Music, #945  Sturgeon Bay, WI