Black water Backs Up Into Grey???

[PDB]

I seem to have developed this problem ever since the dealer pumped out my tanks.
I usually dump the black with the SaniFlush running, then dump it two or three more times until it dumps clear water. Then I dump the grey. Ever since the dealer pumped out my tanks I've had two problems occur: 1) when I dump the grey, it definitely appears half-black; and 2) the toilet no longer retains water overnight.
Could these be related? Any idea what might be wrong with my tanks?
Thanks for any help.
Paul

[PDB]

I seem to have developed this problem ever since the dealer pumped out my tanks.
I usually dump the black with the SaniFlush running, then dump it two or three more times until it dumps clear water. Then I dump the grey. Ever since the dealer pumped out my tanks I've had two problems occur: 1) when I dump the grey, it definitely appears half-black; and 2) the toilet no longer retains water overnight.
Could these be related? Any idea what might be wrong with my tanks?
Thanks for any help.
Paul

[RV Wizard]

It could be related. How, exactly were the tanks "Pumped Out"?

[Bob (WA0MQE)]

Sounds like they might have used to much suction and damaged your seals on the toilet and possibly the knife valve seal at the grey dump.

[bsinmich]

Toilet paper getting caught in the sliding valve of a Thetford will definitely let the water out. A coat hanger and a mirror will let you see in the small opening and you can poke out the TP with the end of the hanger. I would not be totally sure about black water in the grey. Aftter a while you will find the grey tank can get to smell as bad as the other one. Try driving with 1/2 tank of water in each tank and put a bag of ice cubes in each. By the time you have gotten to your destination you should have gotten the walls much cleaner. Do not use any unmelted icecubes in your drinking water!!

[dieselclacker]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bsinmich:
Toilet paper getting caught in the sliding valve of a Thetford will definitely let the water out. A coat hanger and a mirror will let you see in the small opening and you can poke out the TP with the end of the hanger. I would not be totally sure about black water in the grey. Aftter a while you will find the grey tank can get to smell as bad as the other one. Try driving with 1/2 tank of water in each tank and put a bag of ice cubes in each. By the time you have gotten to your destination you should have gotten the walls much cleaner. Do not use any unmelted icecubes in your drinking water!! </div></BLOCKQUOTE>

[PDB]

I can't say how they emptied the tanks, the dealer took the coach, disappeared for 15 mins, brought it back and said "All done".

RE: Grey smell. Yes, you're right, the grey can certainly smell bad. But I'm talking about the color of the water during the dump process as it comes thru the transparent drain pipe.

I've tried several things to clean the knife valve and it seems to be getting better. The trick that seems to do the most good was to keep the bowl 1/2 full all the time. It leaks down a lot slower now. I've tried to buy the 'special tool' but haven't found it yet.

[DSouthw524]

You can make the special tool easily. Buy a cheap flat blade screw driver with a slender blade. Use your propane torch to heat the area just above the head and bend a right angle in the shaft. I also suggest attaching a thong or similar to the handle (drill a hole) of the device as you can them hang it somewhere when not in use.

[M&EM]

use a long thong that can be permanently secured at the other end. This way you can retrieve the tool if you accidently drop it thru the hole

[Ray,IN]

Instead of using a sharp object to clear the bowl seal, I use an old toothbrush, and a string attaching it to my wrist. After cleaning, I coat the seal with silicone rubber lube. The tank valve is not so easy to clean, it must be dismantled. It's a dirty job but someones gotta do it, and I can't somehow picture my wife doing it. And NO, before you say it, it isn't my wife's toothbrush.

[Ken Roberts]

bsinmich, I agree ice cubes in the black tank every once in a while is a good idea; but, for the life of me I have never figured how to get the ice in the grey. What is your secret? Ken,'04 DSDP...