Regal 3300 Owner's Manual page 205

TO CHANGE FILTER, UNSCREW UNIONS
On electric toilet installations a waste filter is connected between the
overboard hull vent and the waste tank. It eliminates the majority of
the ingredients that cause waste system odor. It is recommended that
this filter be changed once per year.
Refer to the equipment manufacturer's manual for additional
information.
Toilet-Electric w/Pump Out Fittings
Read the manufacturer's recommendations regarding toilet paper type
since household varieties are not usually "friendly" to the onboard
system or the marine environment.
As part of your pre-cruise inspection monitor the waste tank level
and obtain a pump out before undertaking any extended day cruising.
https://www.boat-manuals.com/
Electric toilets feature a deck fitting that permits
a marina or waste station to pump out the vessel
waste or holding tank. A hose attachment screws
into the deck fitting and removes the waste in
the vessel toilet holding tank by activating a land
pump.
Features
6-45