One head or two, Barry?
Trust me, you DON'T want an electric toilet that can revert back to manual...all you'll really have is a manual toilet with a motor on it that does nothing but replace the pump handle, which makes for a poor excuse for an electric toilet. You want either a manual toilet, or a true electric macerating toilet...not a hybrid. If the boat has two heads, and you're that concerned about a complete power outage (the toilet will be the least of your problems in that event) put an electric toilet in one, a manual toilet in the other. If you're installing a Lectra/San, why would you need a huge holding tank? The only time you'd use the tank is when you visit any "no discharge" harbors or marinas...and you certainly don't want to have to deal with pumpouts as a live-aboard if you don't have to. That may mean installing two Lectra/Sans if you have two toilets, unless the L/S can be within 6' of both...which isn't likely if the heads are at opposite ends of the cabin. Your best choice for a toilet is one that uses onboard pressurized flush water...lowest power demand, lowest flush water volume. My choice is the Raritan SeaEra (also available in two raw water flush models). However, unless you bought the salt tank designed to be used with a pressurized water toilet--the 4 gallon tank with pump--you'll have to exchange the salt feed tank for that one. We should prob'ly have some real conversation about the best system for your boat and your family's needs, and the best way to install it, before you do anything.
