hi can anybody recommend any thing to get rid if the sludgy deposits which seem to have built up in the water supply which flushes the loo. everytime the loo is flushed bits of stuff come out from the supply hole. ive tried blowing down the filler neck on the side of the van and do get a bit coming out off the drain tube. the vans a 93 challenger 510/4. anybody know anything about these probs etc. many thanks steve