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Old 06-27-2014, 10:01 PM   #1
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Waste Tank Management Question

This is probably a stupid time to ask this question since I have owned my motor home since last August. However, I am going to ask it anyway. I am parked in a campground in Fayetteville, Arkansas. I will be here for over a week, because my son was involved in a pretty serious accident involving a motorcycle. Hit a deer in the Ozark Mountains doing 55 mph. My brother, who has operated RV 5th wheels and tag alongs for years, told me to keep the black tank valve closed all the time, until it is almost full. He told me to keep the gray tank valve opened, once sewage connections were made. He told me to dump the black tank when it got to at least 3/4 full, and then to open the gray water tank to flush the lines. Forgot to say that I was supposed to close the gray tank valve a little bit before dumping the black tank to ensure there was ample gray tank water to flush the sewage line. I was then supposed to close the black tank valve, put some deodorant back in the black tank through the commode, flush some clean water in the black tank using the commode valve, and then press on with the gray valve remaining open until right before until black tank dump again. I guess I'm saying to keep the gray valve open all the time except for shortly before a black tank flush. And the black tank valve stays closed all the time except for when I am dumping it. Does this make sense? Am I doing it right? I know that when I keep the gray valve closed, it does not take but one or two showers to fill it up. Am I doing this right? Thanks for the participating in the long read.

Jim & Judy & Bella (Black Lab) & Sunny (Retriever)
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Old 06-27-2014, 10:08 PM   #2
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Think you will get multiple opinions on this subject. Not saying my way is better than others, however, I leave my black closed, and gray closed. When I dump, first do black, then gray to flush the lines. I prefer to have as much gray as possible to flush the black. Usually try to dump once per day, but have gone multiple days before dump. Really depends on how much shower and laundry use we have from one day to the next.

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Old 06-27-2014, 10:10 PM   #3
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Sound just fine to me , my coach has a washer / dryer combo so the grey stays open till just before black dump.
Reason for the black tank closed is to have fluids in the tank to partially dissolve the solids and flush them away. No liquid, then solids will stick and build up on the bottom of the tank.
In some cases no amount of flushing will clear that mess out.
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Old 06-27-2014, 10:14 PM   #4
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The best practice is to leave both closed until ready to dump. The black should be as full as possible. We alway stand with our foot on the flush until it is full. The more fluid the better it will carry out the solids. After black tank drain, close it and drain the grey to wash out your drain hose. Depending on your grey, you may need to drain it more often but just remember you'll need some to flush the hose with.

The other tip is after draining the black, never let it dry out. Alway put a little water in it even if in going to be stored. The dried stuff is what causes the odor that people complain about and will build up over time. Even in the winter, I have a little water in mine and add some antifreeze.

It does not hurt to put some chemical in if you want.
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Old 06-27-2014, 10:39 PM   #5
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Brother is right. I like to have the gray tank about half full when it's time to dump. The catch is in most RVs the gray tank fills up about 3X as fast as the black. You need to fine tune for your family's lifestyle.
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Old 06-28-2014, 12:57 AM   #6
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I leave both closed until I get a full indication on the black or grey tank. Then I flush the black first followed by the grey tank. I then go back inside and put a black tank treatment packet in the toilet then do the #2 flush 4 times to get water in the bottom of the black tank. When we get ready to travel I pour a bit of pine sol in the black tank. The movement of the rig will slosh the water around and clean the tank walls and probes. Well at least that's the theory.
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Old 06-28-2014, 08:52 AM   #7
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Waste Tank Management Question

Jlabit.... Two quick points: first, everyone's jumping into the tank-- so to speak-- but I think the most important thing here is your son. I hope he's recovering, and will emerge with no permanent effects. Please keep the forum aware!

Second, as you've seen, there's variation in the way folks handle these things. The consistent important point is that the black tank remains closed to accumulate waste, and is then dumped as a single action.

The business with the gray tank is optional, depending on whether you're boondocking, want to conserve water use, whether you have or don't have an integral black tank cleanout/flush system, etc., etc. the main point is that the black tank stay closed until ready to dump.

Also note that the advice you receive comes from varied sources. The imperatives of tank management will be different if you fulltime, as opposed to someone who takes 5-6 trips a year. Absent proper use management, the likelihood of problems increases if your RV is parked intermittently and your tanks have a chance to dry out.
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Old 06-28-2014, 09:46 AM   #8
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Hope your son has a full recovery! I have hit a deer with a car and that caused a lot of damage to the car but I was ok. I can't imagine hitting a deer on a motorcycle.

My thoughts on the gray tank is that I want to have it pretty full to wash out food particles from the kitchen sink so I need the most water flow to do that. I leave the gray closed as well as the black and only dump when needed. A friend had to have their gray tank flushed when it wouldn't drain (it took several years to happen) but when that tank was flushed by the pro you wouldn't believe the gunk coming out. Guy said it was residue from soap+grease, food particles and toothpaste (he showed them the dirty details- I didn't participate in that! That made me a believer in lots of water to stir things up when draining.
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Old 06-28-2014, 10:32 AM   #9
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For the kitchen sink I purchased one of those drain sieve things. It stops most of the accidental food particles from going down the drain but lets water go thru. I think it was $2 at Lowe's or something. We juice so just about every day I am making fresh veggie/fruit juice for breakfast. Lots of particles to maybe go down the drain, I wanted to stop most if not all and it helps there.

As for when to dump .... keep the black closed until it is at least 3/4 full, add in extra water every now and then to keep things NOT dry in there. Right now the temps where we are at are going into triple digits so I try to make sure it does not dry out in that tank, nasty job to fix a blockage in these things. Even with a 100 gallon grey tank I am dumping it every 3 days or so from cleaning the juicer. It depends on where we are at as to whether we keep the grey open till almost ready to dump the black or to keep the grey closed until I am ready to dump. Some CG's have things in the sewer lines that I really don't want crawling up the lines so I do what I can to stop that too. Some CG's don't have that problem.
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Old 06-28-2014, 11:21 AM   #10
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OMG! Black tank closed to prevent Poop mountain. Gray tank is optional as long as when you do dump the black there is something in the gray to flush out the hose. If I told ya how many times a customer would come into the dealership with a pluged up Poop tank you would die. One other thing " if you didn't eat it don't put it in the toilet"
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Old 06-28-2014, 11:33 AM   #11
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Before adding chemicals or whatever you use in the black tank, you must dump enough water into the tank to first fill the 3" drain pipe that goes from the tank to the valve! then add your stuff. If you add your treatment first, it will travel down the pipe to the valve and sit there, doing no good for the waste that is in your tank.

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Old 06-28-2014, 12:09 PM   #12
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Only comment I can make is when you dump the black, close the black tank valve before opening the gray tank valve to prevent back flow from one tank to the other. Only one valve should be open at a time.
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Old 06-28-2014, 12:44 PM   #13
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Old 06-28-2014, 01:35 PM   #14
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Thoughts and prayers are with your son in hopes of a speedy recovery.

All good advice so far IMHO.

There's not a single "right answer" to the question but once you understand the basics and learn how to use your systems, you'll develop your own processes.

Although I will sometimes leave my grey tank valve open for a while, mostly I keep it closed and only dump when it's near full. I never leave the black tank valve open and "try" to only dump it when it's > 1/2 full but often times I'll just use my San t Flush to fill it with more fresh water before dumping. I then usually let it rinse for a while, then close the black tank valve letting the tank again fill to ~1/2 full with fresh water and then dump again before closing the valve and running around 10 gallons of fresh water into the tank. Never let them be dry.

We have an ice maker so I often times dump before breaking camp... add the 10 gallons of fresh water... and then dump all of our ice down the toilet just before we hit the road. The ice sloshing around tends to dislodge stuff stuck to the sides of the tank.

Best of luck.


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