cleaning water tanks

[wmrayt]

I have tried to fluch and clean the water tank on my 77 Champion. It has black junk clinging to the inside walls of tank. A lot has come out flushing but still a lot in it. I have used bleach so far and drove around to agitate.

Thanks

Ray

[Funding Fun]

The black slim is tough to deal with...all bleach does is turn it clear. I had the same issue with the tank on my boat and had to remove tank to clean. If you can get ice in the tank along with the bleach, then drive like Kevin Harvick for a few miles it may knock it off but you would never trust it to completely remove it. How much trouble would it be or can you even remove tank?