Best of the best: black tank deodorizers

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Wrdabney

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Jun 27, 2010
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I am staying in Mississippi for a couple of months working. I am living in my 29' tt and the temp during the day here is usually over 100 with heat indexes reaching 120's. It usually takes me and my significant other 4-5 days of use before the black tank needs emptying. However, it only lasts about 2-3 days before it gets that ripe smell when flushed. Is there any way around this. Anybody have an opinion on the most potent or effective deodorizers for my situation?
 
I'm lettin it get close to full. Isn't it bad to just leave the valve open?
 
Yep, it's very bad to leave the valve open.  Although you'll find opinions on this all over the map I think general consensus of the more experienced in the group is that we don't really need to use anything so long as you empty the tank when it's nearly full and flush it out regularly.  Haveing said that, I now use 1/4 cup of Dawn dishwashing detergent to help with a flush and rinse process and sometimes add a half cup of bleach too to kill odors.  I add at least 8 gallons of fresh water, Dawn, and maybe even bleach in hot weather so I start with pleanty of liquid in the tank.

 
I have tried dishwasher soap and rinsed with that. It didn't help much. It says in the library that it's bad to use clorox because it can eat at seals.
 
The first thing is, do you run the fan in the throne room during use?  It could be sucking up gases from a partially full tank when the flush valve is opened.

Then check your vent.  It could be some critter taken up residence or debris like leaves gotten into it.

A bacterial product like Robex may help.

Failing all else try an enzyme-based deodorant.  Avoid 'tank treatments' with a formalin/formaldehyde base.
 
I usually use the fan but mine sucks air out of the bathroom. I was gonna check the vent on top but there was caulking around the screws. I didn't wanna mess that up but I guess I'll take them off and re caulk.
 
Wrdabney said:
I usually use the fan but mine sucks air out of the bathroom.

That's the problem. When you suck the air out of the bathroom, it has to be replaced, nature doesn't like a vacuum. When you flush you suck it right up from the holding tank.
 
I didn't think about that. I'll switch the wires on the fan and reverse it. Seems like a fan blowing in though would be kind of pointless. Wouldn't it just disperse the stench in the bathroom or tt.
 
Just turn the fan off when you flush, then turn it back on.  You don't want the fan to blow in.  But also check the vent for any blockage.
 
I use only water in my black tank less I'm parked w/o hookups for more than 4 days.

In another post I mentioned having more important things to do today.

I tell people I do Light RV repairs and maintance.. Not today though.

You see.. This rig is a "Bath and a half" model. the "Half" is also my ham shack, comes in handy if you are in a net, awaiting your turn, and just as you feel that old "Call of Nature' and find you have an "Urge" to go someplace.. The NCS (Net Control Sataion) Gives out your call... You see.. I'm already there.

Well.. Due to a small, unnoticed leak, and some idiot who thought that under the toilet was a grand place to plant carpeting..  The chair came loose from it's mount.

Now this is a MAJOR repair.

So today.. I dissembled the toilet.  Set the bowl aside, Cut the mounting bolts off the base, (Cleaned the seals while I was at it)  Cut out the rotted wood. cut new wood to replace it, adding a support or two cause of the way I did the cuts.  sealed the wood (Sealer stain) so if it gets wet it won't do so much damage. This is also a primer I will paint later.

Bolted the base back on (With additional sealant between base and plumbing) re-attached the bowl and it's plumbing and tested.

I now have a very sold operator's seat once again.  No leaks evident.

So, what does this have to do with this thread.

There was NO STINK from the partially filled black tank.. NONE at all while I was working

AND THE PIPE WAS OPEN

Now the GRAY tank.

When I last dumped.. The moment I opened the GRAY valve,, The Nose Knew it.
 
You can probably defer the odor longer if you use more water when you flush, but then you have to empty more often anyway (which also solves the problem, eh?). 

I doubt if you have a vent problem since it takes 3 days for an odor to first appear.

Any enzyme/bacterial based black tank treatment will do the job if you thing you need something. Pure Power is one often recommended brand, but most any brand will do. A septic treatment like Rid-X or Roebic 57 might work as well, but add it in well before the odor appears.
 
It could be that after 3 days the vent lower end is covered with liquid in the tank and that would cause the same symptoms.  I agree the vent is not blocked.
 
Yeah it usually takes 2-3 days before I notice. Sometimes I don't have the fan on when I flush and I can still smell it. Maybe with the heat it's normal to smell something after 3 days (am I wrong?)
 
Mine does not and we've been camping continuously in 94-101 degree weather since late May, but I've heard others say they have noticed a smell in very hot weather that they had not had before.
 
We notice it more in our current motorhome than previous ones so I suspect it has something to do with design of air circulation about which nothing can be done, except as mentioned above, namely turn off fans when flushing.  It's worse in very hot weather.

ArdraF
 

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