gaffcat wrote:
I have a Traveler toilet that sits right on top of a 90 gallon holding
tank. The toilet dumps directly with gravity and works great. The tank
can be emptied with a standard pump-out fitting or I have an electric
pump that I can use to empty the tank directly overboard which of
course I only do if I am offshore where it is legal. The electric pump
pumps from the top of tank with a dip tube to the bottom. The direct
discharge pump and the pump-out set up use separate piping.

You aren't gonna enjoy checking this out...but I suspect that either the
end of pickup tube is cut flat instead of at an angle and is also too
close to the bottom of the tank or the accumulation of sludge in the
bottom of the tank has gotten so deep it's clogging up the pickup
tube...or both.

It's not THAT hard to flush out a tank....in fact, since you have two
separate discharge fittings, it's actually very easy and can even be
done at sea if you have a washdown pump.

It's not necessary to fill the tank...you only need enough water to stir
up the sludge enough to put in suspension so it can be pumped out.
Stick the washdown hose into the deck fitting...start the overboard
pump...and just keep the water flowing till what's coming out the
discharge is clean water. Voila...both the tank and the pump are clean.
You don't have to do it every time you dump the tank...2-3 x a season is
enough to keep the sludge level down.


Would I be better off with a macerator pump?

You'll have problems with any pump if the end of the pickup tube is
buried in sludge.



--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books...ku=90&cat=1304