RV Repair: Plugged black water tank, rv toilet, tank company

Question
My permanently parked 5th wheel was draining fine until it just started filling the black water tank. I tried back flushing from the gray water but no luck. I've used digester and I even put a plumbers snake down the toilet to no avail. I tried from the bottom but I can't get in more than 3 or 4 feet. Any help would be greatly appreciated as I really don't want to drop the cover of the bottom of the RV if I don't have to. All the screws are very rusty. Thanks.

Answer
David...when living in an RV you still have to operate the sewer system just like an RV not a house. You cannot leave the black water drain valve open without complications arising..like "plug-up".
When you flush an RV toilet there is not enough water flow through the tank to force the contents out and down the drain system. So the liquid flows out and the solids stay behind and build up in time, causing a mess. If its bad enough the tank may have to come down. You can try to "rehydrate" the contents of the tank ,but that takes time. You would have to fill the tank with water and chemicals and let it sit for days and even then it may not work.But it is worth a try. If not, call a septic tank company and see if they have any experience with you type of problem. If they don't, don't let them help. I've used them in the past, and it has worked.
Good luck.

Thom
RV-PHD