Dumping question

[Mellis]

Hello everyone I am new to the forum so. I have a Quantum RC 25. I have two black tanks, one as usual with the gray tank and another under the toilet. Simple question when I dump do I open that first and close last? I think I am supposed to leave it open when in use. Please some help.

[sanjaun2]

Are you sure you have two black tanks? Most people will tell you to leave the valves closed until ready to dump. Empty black tank first, Then drain grey tank. This will help clear the lines of black material.

[Mellis]

Yes I definitely have two black tanks and in the walk through they gave two different answers and I did not realize it until I went through the video. It’s only on some RVs.

[Bob Denman]

Welcome to the forum!
Leave the valves closed until your tanks are nearly full. Then: dump the black tanks first.

[sanjaun2]

I wish I had two tanks, better yet two water tanks! On my RV I have one black tank that has two valves. I hook up the hose then open black valve by connection. Then i walk around to the other side of RV and open the 2nd black valve under the tank which is below the toilet. No one told me about the 2nd valve so first time dumping nothing happened! I call RV dealer and they knew nothing either! I looked under the motorhome and found it!

[paulwadley]

The tank valve under the mh on the passenger side holds the black tank fluids back from the black tank valve on the driver side. It is a safety valve in the event your crossover line gets damaged while driving. It will not allow the black tank to empty. Just hook up your slinky to the dump station, go to the passenger side and open the valve. Go back to the driver side and open the black tank valve to dump the black tank. When empty, close the passenger side valve and then go back to the driver side and close the black tank valve. You can now empty your grey tank to clean out the slinky. Some trailers do have two black tanks, but most rv's have only one.

[abjbrtd]

Originally Posted by Bob Denman

Welcome to the forum!
Leave the valves closed until your tanks are nearly full. Then: dump the black tanks first.

If you don't keep your black tank(2) valves closed you'll end up with a "blank tank pyramid".
Google it
The solids in the tank will harden
Pretty common practice is to keep the gray tank open most of the time, close it the day before you drain the black tank. Open it after dumping the black to clear the hose.

[Bob Denman]

Yup!
I use my San-T-Flush aggressively, and have never had a problem.

[EA37TS]

Everyone has their own way of doing things. I keep the black tank closed and when connected to sewer the gray tank open. When the black tank gets to 1/3 I close the grey tank to get a little waste water in the tank. When the black tank gets to 2/3 or more I will dump the black tank, close the valve and then use the black tank flush to fill the black tank to 2/3 and dump again. I will do this until the water runs clear when viewed through a clear hose connector. Once the water drains clear I will come the black tank valve with the black tank flush still running for about 15 to 20 seconds to put a gallon or two of water in the tank. I will then open the. grey tank valve to flush the sewer hose. That completes the dump cycle unless I am departing and then I'll make sure all tanks are closed and hoses disconnected and stored.

Been doing it this way for decades with no issues or smelly tanks.

[hatwate]

We keep all tanks closed until we dump. We first dump just a bit from the gray tank to make sure all the lines are still open and not leaking anywhere then we close that, dump the black and then the gray to cleanse the lines. As my husband says, you don't want to dump the black then find out too late that there is a problem with the lines/hoses.

[Golfbum18]

Originally Posted by Mellis

Hello everyone I am new to the forum so. I have a Quantum RC 25. I have two black tanks, one as usual with the gray tank and another under the toilet. Simple question when I dump do I open that first and close last? I think I am supposed to leave it open when in use. Please some help.

I dump every day and that keeps the crap, grease from the grey water, and TP from the black to not build up on the sides and screw up the sensors. After all, you're camping....you have 5 minutes each day to do it. But keep your valves closed to keep out any sewer flies that will fly up your plumbing and into your bathroom etc. Black first then rinse the hose with grey...simple After all, if you don't flush the black water outta your hose with grey, it's gonna stink and get real, well you know......crappy. Since following this regimen, I have not had false sensor readings or smell from the tanks. Every day.....thank you and good night.

[rynosback]

Originally Posted by sanjaun2

I wish I had two tanks, better yet two water tanks! On my RV I have one black tank that has two valves. I hook up the hose then open black valve by connection. Then i walk around to the other side of RV and open the 2nd black valve under the tank which is below the toilet. No one told me about the 2nd valve so first time dumping nothing happened! I call RV dealer and they knew nothing either! I looked under the motorhome and found it!

It’s all about space but more so the weight.