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Author Topic: Best way to help reduce black tank odors.  (Read 3411 times)

CP

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Best way to help reduce black tank odors.
« on: May 12, 2013, 06:17:09 PM »
Just wondering what others do to help reduce black tank odor?
Not expecting to be greeted with the most pleasant of odors after flushing in the MH (2011 Fleetwood Terra)?
But we are certainly open for ideas to help reduce odors. Currently we are only using Pure Power waste digester and odor eliminator in the tank as recommended.

Thanks in advance!
Chuck
Chuck
2011Fleetwood Terra
2011 Lincoln MKZ Hybrid

SeilerBird

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Re: Best way to help reduce black tank odors.
« Reply #1 on: May 12, 2013, 06:34:24 PM »
The first thing to do is to stop using the chemicals. They are not solving the problem, they are covering it up. If you do it right you won't need chemicals at all. What you do need is water, lots and lots of water. When I dump my black tank I put about five gallons in it to start with. Every time I use the toilet I hold down the flush lever and count to five. That's all you got to do.

Now if you are boondocking then you will need to dump the tanks when they are at least 3/4 full. Don't dump with any less than that or it won't take all the solids out of the tank. If you are hooked up to a sewer then keep the grey valve open at all times but keep the black valve closed until the tank is at least 3/4 full, then dump, then close the valve again.

If you have been hooked up to a sewer and keeping the black valve open you might have developed a poop pyramid when the poop lands in the tank and doesn't get flushed down the sewer line. If you do have a poop pyramid it could take an effort to remove it.

Bottom line, you should not have any odors coming from your toilet without chemicals. Actually I do dump a few squirts of Dawn dishwashing liquid into the black tank after dumping to give the toilet a sweet smell.
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Bill.Winegard

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Re: Best way to help reduce black tank odors.
« Reply #2 on: May 12, 2013, 09:05:23 PM »
Turn off your exhaust fan while flushing, use plenty of water while flushing, wait to dump until you are 1/2 to 3/4 full and do nothing else.
Bill Adams
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srt20

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Re: Best way to help reduce black tank odors.
« Reply #3 on: May 12, 2013, 09:34:53 PM »
Google "geo method" it works, it's safe, and it's cheap.

Bob Buchanan

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Re: Best way to help reduce black tank odors.
« Reply #4 on: May 12, 2013, 09:56:43 PM »
Are the flush seal holding the water OK after you flush? That inch or so helps keep the odors where they belong. There was/is another topic with that subject if I recall.
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Wigpro

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Re: Best way to help reduce black tank odors.
« Reply #5 on: May 13, 2013, 01:34:09 AM »
The black tank and toilet smelled terrible when I bought my used 5th wheel. I discovered that I had the dreaded poop pyramid, the previous owner obviously had little experience with an RV tank. So the first thing I did was empty the tank as best I could, I was in an RV Park with hookups, so I was able to dump....then I filled the tank with a full hot water tank of hot water....and added some dawn dishwashing liquid, not too much just a good long squirt. Went to bed.

The next morning I was traveling so I emptied the hot water heater again in the toilet. Now the blackwater tank was almost 3/4 full. I pulled out and stopped at the park office and bought two large bags of ice. I dumped both bags of ice in the toilet and then drove for about 100 miles....when I arrived at the park I hooked up and dumped the blackwater tank, then I filled the tank with another hot water heater full of hot water, another squirt of Dawn dishwashing liquid and then filled the tank back up to 3/4 and dumped it again.

It has not smelled since in two years and I use plenty of water when flushing and only empty when at least 3/4 full. I never leave the back valve open when on sewer hook-ups, I actually keep both my grey and blackwater closed and dump when nearly full. I leave the hose hooked up but the gate valves closed. I dump the black first and when that is finished I dump the grey to flush the hose out.

I have never had the need to use any chemicals and doubt I ever will. I can even leave the fan running when I flush and don't get an odor, at least nothing worse than what I just put in!!!

I have a four flush rule in my RV. Fill the bowl, do your business, flush and fill the bowl three more times and flush.


Good Luck.

Jim
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COMer

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Re: Best way to help reduce black tank odors.
« Reply #6 on: May 13, 2013, 06:10:02 AM »
What everybody else says.  I used to use chemicals and dealt with odor often.  Since I quit adding anything except water, it has been odor-free.  Use water only.  Plenty of it and dump when it's 3/4 full.  Easy.
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CP

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Re: Best way to help reduce black tank odors.
« Reply #7 on: May 13, 2013, 07:05:06 AM »
Thanks everyone for your help.  I added lots of water and nearing the point to dump black tank.
Hopefully things will come up Rosie (or something like that).

Thanks again.
Chuck
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trishnikollic

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Re: Best way to help reduce black tank odors.
« Reply #8 on: May 13, 2013, 07:18:30 AM »
Wigpro has well said in this context. I think, you may go with his advice.

Gary RV Roamer

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Re: Best way to help reduce black tank odors.
« Reply #9 on: May 13, 2013, 08:35:40 AM »
Pure Power is a good product and not causing your problem, but more chemicals won't help either. You could have the poop pyramid problem if the black tank has been used with no water in it, i.e. the drain valve was left open. It needs to have liquid in the tank for the solids to dissolve and the waste & odor eating bacteria to thrive. Otherwise, I don't think that is the problem.  And while you should use adequate water to flush, I don't think you need to go overboard either. A normal single flush works fine for us.

There should be no smell at all when you flush, so something is clearly wrong. My first step would be a thorough rinse, fill and drain the tank a couple of times and use a tank rinse tool if you have one. Then I would fill the waste tanks (gray & black) with fresh water and add a enzyme-based septic treatment and let it sit for 3-5 days and then dump and rinse and dump again. I like the Roebic K57 or Rid-Ex enzyme products for cleaning, but your Pure Power is probably ok too. See if that gets rid of the ongoing odor problem.
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tvman44

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Re: Best way to help reduce black tank odors.
« Reply #10 on: May 13, 2013, 08:39:18 AM »
All we use is water. :)

scottydl

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Re: Best way to help reduce black tank odors.
« Reply #11 on: May 13, 2013, 08:56:02 AM »
You might also want to invest in an "RV Hydroflush" extension for your tank output hose.  Helps you see (literally) what is rushing out of the tank... sounds gross but is actually helpful... and allows for a backflushing of the tank by connecting a hose from the outside.
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COMer

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Re: Best way to help reduce black tank odors.
« Reply #12 on: May 13, 2013, 10:12:21 AM »
Chuck,
If you don't have enough in the black tank to flush, but want to, you can always add water until you are at the 3/4 point and then do it.  That way you have plenty of fluids to escort the contents out.
John & Darla
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John From Detroit

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Re: Best way to help reduce black tank odors.
« Reply #13 on: May 13, 2013, 10:44:34 AM »
I have never reallly noticed a serious black tank odor issue.. Even when I had the toilet off fixing it so the tank was open.

EXCEPT For one time.. That one time I'd dumped tanks and FORGOT to close the valve.

Now the gray tank.. With all that food and grease in it.. That gets downright stinky.

But not so much the black.

The best advice I can add to what is above (I don't like chemicals eiother and don't use 'em) is close the stinking valve.  OR.. Trap the line..more on that.

Some places have rules that state the hose must slope toward the hole in the ground (no low spots) if this is the case you can not trap it.

I have 3 tanks.

Black, Gray and Wash (The wash tank does NOT get any water from the kitchen sink, only bathroom lav's and shower)  This last tank I normally drain via a 3/4" Garden hose (Also gray, gray hose = Gray water, color coded,, Yes I have a black garden hose too, and a macerator pump for those cases where it's needed).

Back to topic... That hose, needing only abourt a one inch rise to "Trap": I do leave open. (Wel;l the dump valve)

But the big hose I close the valves and no problem.. The one time I left ;'em open, big stink.
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Jack Siegrist

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Re: Best way to help reduce black tank odors.
« Reply #14 on: May 13, 2013, 01:30:02 PM »
Another good way to get complete dumping of the black tank is to drain it first and then open the gray tank valve and allow it to backflush into the black tank so that the soapy residues from the gray tank can act on the black tank contents. I usually let it work for about five minutes before dumping the whole thing. Only works if you have a pumpout system. Jack

scottydl

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Re: Best way to help reduce black tank odors.
« Reply #15 on: May 13, 2013, 06:27:33 PM »
Another good way to get complete dumping of the black tank is to drain it first and then open the gray tank valve and allow it to backflush into the black tank so that the soapy residues from the gray tank can act on the black tank contents. I usually let it work for about five minutes before dumping the whole thing. Only works if you have a pumpout system. Jack

I don't think I've ever heard of this method... but it just might work?  I'm thinking of a typical "1 drain" system where the two tanks outlets come together.  Drain the black tank, keep the black valve open, replace the drain cap, and open the gray valve.  The only potential issue would be if you have a larger gray tank than black tank, with the risk of overflow up through the toilet as the gray water fills up the black tank.
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4DogsRV

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Re: Best way to help reduce black tank odors.
« Reply #16 on: May 13, 2013, 06:55:07 PM »
I found this very informative:

http://m.youtube.com/watch?v=gZFyfsy4ptw
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Bob Buchanan

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Re: Best way to help reduce black tank odors.
« Reply #17 on: May 13, 2013, 07:42:48 PM »
I don't think I've ever heard of this method... but it just might work?

     It "does" work, Scotty, and has become standard procedure for me. That is why I make sure I always have a full gray tank when ready to dump the black tank - vs. always leaving the gray line open while in a park. I have a macerator installed so replacing the cap is not necessary. The outlet is connected to the macerator pump by a short piece of sewer hose, so until turned on, the flow stops at the pump. The short length to the macerator is connected by a clear 45 angle so I can see what is going on during the process.

Yes, it's important to limit the backflow and make sure the gray tank "does" contain water. Otherwise, the backflow will go the other way and that would not be good. Tank dumping is not something to start and do something else while it is happening.  :)
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CP

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Re: Best way to help reduce black tank odors.
« Reply #18 on: May 14, 2013, 08:15:47 AM »
Looks like we are good to go now.  I did a good flushing (no pun intended) a couple of times and it made all the difference. I have a feeling we did not have enough water to begin with as I thought we had.

You are all great to help out.  We just bought our first motorhome late last fall and are now on our first trip this season and having a great time (with a little help from our forum friends).

Thanks to all.
Chuck
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2011 Lincoln MKZ Hybrid

Rich D.

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Re: Best way to help reduce black tank odors.
« Reply #19 on: May 21, 2013, 09:58:55 AM »
I found this very informative:

http://m.youtube.com/watch?v=gZFyfsy4ptw


By using the gray water to flush out the black tank you can accompliush the same thing as shown in this video but to it in a fraction of the time.

1.) Dump the black and leave the valve open.
2.) Open the gray valve for 3 or 4 seconds. Some gray goes down the drain and some backflushes into the black tank.
3.) Close the gray valve. Watch the black tank drain the gray water back out taking waste that was left from the first draining with it.
4.) Repeat #2 & 3 until black tank runs gray. (Usually only one more time.)
5.) Close black valve and fully drain the remaining gray water.

Simple, quick and easy; you don't need to connect a hose or wait minutes for the tank sprayer to add water to the black tank.

(Edited to correct spelling, typos.)
« Last Edit: May 21, 2013, 11:41:49 AM by Rich D. »

Ned

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Re: Best way to help reduce black tank odors.
« Reply #20 on: May 21, 2013, 10:19:02 AM »
Most of the holding tank drains I've seen would make it impossible for the gray water to back up into the black water holding tank regardless of the valve settings.  The black tank on our coach drains straight down through the 3" pipe while the gray tank is teed into the 3" drain.  It is physically impossible for the gray water to back up into the black water tank.  That would require a 3rd valve be added to the 3" drain below the tee fitting, and even then I doubt more than a few gallons would actually get into the black tank.  A tank flush is much more effective.
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Rich D.

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Re: Best way to help reduce black tank odors.
« Reply #21 on: May 21, 2013, 11:35:12 AM »
Ned,

You must take into consideration the length of the sewer hose, the slope of the hose toward the sewer and the height of the sewer connection pipe. Trust me, this works in most every situation. The pressure to push the waste water down the hose is greater than what is required to send some back into the black tank. I've been doing this for years (20) with several different motorhomes ant it has always worked! Try it next time out if you don't believe me.

You only want a few gallons to backflush - about the same amount as shown in the video.

Ned

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Re: Best way to help reduce black tank odors.
« Reply #22 on: May 21, 2013, 11:56:59 AM »
I can tell you it won't work with our drains.  The gray tank drain is only 1.5" while the sewer hose is 3" so there is no back pressure whatsoever when the gray tank is drained.  It all goes straight down.  Even if some would back flow into the black tank, it won't be nearly as effective for cleaning as a typical flush spray.
-- Ned -- Fulltimer 1997-2013
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Bob Buchanan

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Re: Best way to help reduce black tank odors.
« Reply #23 on: May 21, 2013, 12:44:08 PM »
My gray into the common 3" is only 1.5", Ned. That's why I would take the extra step of unhooking the 3" hose and recapping the outlet prior to the backflush. Then the gray will seek it's own level with no lose of head pressure. Leaving the main hose open "would" cut down the pressure a lot with only 1.5" coming from the gray. As you know, regardless of the size of the two tank hoses, if left on long enough, both tanks will wind up at the same level.

Of course, recapping will take a bit longer so needn't be done with every dump. Sometimes we have more time to dump than others.  :)

As mentioned previously here, my backflush is with a macerator connected so the recapping is not necessary.
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Ned

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Re: Best way to help reduce black tank odors.
« Reply #24 on: May 21, 2013, 04:23:33 PM »
And how do you remove the cap after the drain pipe is full of liquid without making a mess?
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Wigpro

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Re: Best way to help reduce black tank odors.
« Reply #25 on: May 22, 2013, 11:54:43 AM »
And how do you remove the cap after the drain pipe is full of liquid without making a mess?

You can't....trying to use the grey water to clean or flush the tank would be fruitless on most RV's, maybe this is a unique instance posted here, but my black water tank is above my grey water inlet into the dump outlet and I find it hard to believe that it would back up into the black tank, no matter how full it is.

I dump black first and use the grey water to "rinse" the dump hose!

I have no tank smell and use plenty of water in my black tanks so it has enough fluid to break down the waste and enough pressure to dump clean. Water is the key to no smell. A shot od dawn dishwashing liquid in both tanks helps keep them clean as well. I have found the grey water with food waste and grease can get more smelly that the black tank from time to time....the soap helps cut that.
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Ned

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Re: Best way to help reduce black tank odors.
« Reply #26 on: May 22, 2013, 12:15:27 PM »
Quote
You can't....trying to use the grey water to clean or flush the tank would be fruitless on most RV's, maybe this is a unique instance posted here, but my black water tank is above my grey water inlet into the dump outlet and I find it hard to believe that it would back up into the black tank, no matter how full it is.

Thank you, that's precisely my point.
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Re: Best way to help reduce black tank odors.
« Reply #27 on: May 22, 2013, 01:02:41 PM »
And how do you remove the cap after the drain pipe is full of liquid without making a mess?

Oops, guess  you have to buy a small bucket, Ned.  :( Or, use a smaller hose with a valve as part of the hose. My macerator 1" has such a hose valve, tho not needed for backflushing. Sorry, I use a macerator and don't have that problem. There is no cap involved.

Unless the sewer hose stays connected as posted by Rich D., one would have a bit of a blackened gray water mess to deal with.
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Bob Buchanan

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Re: Best way to help reduce black tank odors.
« Reply #28 on: May 22, 2013, 01:20:53 PM »
You can't....trying to use the grey water to clean or flush the tank would be fruitless on most RV's, maybe this is a unique instance posted here, but my black water tank is above my grey water inlet into the dump outlet and I find it hard to believe that it would back up into the black tank, no matter how full it is.

I'm on my 5th RV - and it would work on all of them. It's not necessarily the position of the black tank to the outlet - but rather the position of the high water line in the gray tank relative to the bottom of the black tank. If the bottom of the black tank is below the high water line of the gray - it would seem to me that it will backflush until the two water levels are equal.
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Rich D.

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Re: Best way to help reduce black tank odors.
« Reply #29 on: May 23, 2013, 01:16:54 PM »
I'm on my 5th RV - and it would work on all of them. It's not necessarily the position of the black tank to the outlet - but rather the position of the high water line in the gray tank relative to the bottom of the black tank. If the bottom of the black tank is below the high water line of the gray - it would seem to me that it will backflush until the two water levels are equal.

Exactly. Thank you.
You don't have to wait until they equalize...  just long enough to put a few gallons of gray into the black because any heavy residue is on the bottom of the black tank.