I have built an rv from a short school bus. I ran a hose from the "toilet" to a tank in the back to drain the toilet. We wash our dishes in a basin on the counter and dump the dishwater into the toilet to also drain into the tank. I am getting a tannish/white build up in the hose that is plugging the line and not letting it run into the tank. It is the consistency of toothpaste when its wet and when it dries, it is like chalk. Any ideas on what the mixture of urine and dishwater is making? Also, we use vinegar to rinse dishes, so there is a small amount of vinegar going into that hose also.