How to cap black tank at toilet flange?

[laducky]

Hi all, forgive me if this has been addressed previously- couldn't find an answer in my search. I purchased a composting toilet but would like to keep the possibility of going back to a standard rv toilet and black tank just for resale value. Is there such thing as a cap or some plug that can be secured and possibly removed at a later date where the toilet would sit? What have other composters used? Thanks in advance!

[HiJoeSilver]

Not really a good plug for that location. How accessible is the flange right now? How will it be covered?
Since the tank will remain empty I'd clean it well with bleach and then tape some heavy plastic over the flange ensuring a good seal. I'd recommend aluminum foil duct tape since it won't dry out like duck tape. Thin piece of wood over that to protect the plastic.
You could try one of these;
https://www.plumbersstock.com/jones-...FUKRHwodIiEG6A
Think it would need to be 3" though, check the hole in your flange, it might stick up too far if you're putting the composting toilet in the same place though.

[laducky]

The spot right now is empty- gutted trailer rebuild but I would like it as low profile as possible since I don't want to step up to the "throne" haha! I've heard of people combining their black and grey tanks for extra grey storage, but that's not really necessary for my application I would think since water usage on tanks will be relatively low due to the aforementioned toilet. Right now I'm trying to figure out the bathroom rebuild. Not to easy with no straight lines to reference from!