RV Repair: Replacing toilet, converting to portable tank?, home plumbing, plumbing systems

Question
Hi Bill--We have a 1976 El Dorado class C, with a tiny bathroom containing a
toilet, small sink, and hand-held shower. We are going to park the unit
permanently on our land, and want to replace the toilet as well as change the
blackwater system.

We're building a cabin that will eventually use a SeaLand low-flush toilet, so
we want to install that in the RV while we're building the cabin. Because the
RV won't be moved, we want to use one of those portable tote-and-roll tanks
for blackwater, rather than the built-in tank. This way, we can haul it to the
RV dump ourselves, or we can have a septage hauler come and pump it out.

Our instinct is to remove the existing blackwater tank (since it will never be
used again) which will give us better access to the drain hoses (toilet, shower
drain and sink). Are we asking for trouble? Is there a better way to bypass
that old blackwater tank, other than removing it? Any advice on this whole
scheme? It seems like a great idea to us, but we don't have experience in RV
plumbing systems (we are experienced with home plumbing, so understand
that sort of system).

Also, the SeaLand doesn't appear to have a vent, nor does the plastic toilet
that is currently installed in the El Dorado. Do we have to do anything about
this? Does the tote-and-roll tank need a vent? Thanks for any advice!

Answer
As long as you will have ample water I would leave the existing tank and use it as storage. That way you can fill the portable tank when you need to and it also allows for venting from the original system. There will be times when you have to empty the tank now without having the original tank in line and that is when it will become inconvenient. If you decide to remove the tank remember that they all need venting. The only thing that should be on the black system is the toilet and sometimes manufactures put the bath sink as well but not very often.