Originally Posted by dzwiss
Ours will do that when there is a buildup under the down pipe. Pouring a bucket full of fresh water down the toilet usually corrects the problem.
Yup mine will do that as well when the blackwater tank is near full or when I get the build up under the the down pipe (pyramid) as well. I also get a 5 gallon bucket and take the sprayer off of the shower hose to fill the bucket I dump about 3 bucket fulls down the pipe. I dump each one as fast as I can with out over filling the toilet. Then flush you tank again.