Oh yeah, another black tank question

After dumping my black tank and thoroughly backwashing and rinsing, I still get an unpleasant odor inside when flushing toilet.  I have added some Dawn and baking soda.  That helps some but after one week odor is very strong again so I have been dumping tank on a weekly basis.  Am full timing it with my wife.  Before anyone asks, no I do not stick my head in the toilet and hold flush valve open to check for the smell immediately after flushing.  Any suggestions?  Add deodorizers?  Thanks

Is this a brand new RV or did you buy it used? If used then you probably have a poop pyramid in the bottom of the tank. 

Your vent may be blocked (run wter down it to check/clear). A second possibility is that you have the br exaust fan running.

Ernie

Unpleasant odor could be caused by having your exhaust fan running.

Besides what's been mentioned if that doesn't work, Are you getting any kind of smell in any of your faucets?  If you are, you need to sanitize your fresh water system which includes the line going to the toilet.

The black tank is made of polyethalene if im not mistaken and will aborb odors - IF your unit is used it may nothave been cleaned properly, you can go to an rv store and by some shock treatment to elininate the odors but be warned its quite envioronmently harsh so its not always available in every state or province

Under the sink is an air admittance vave (Vacuum breaker) this connects ultimastely not to th black tank but to the gray.. Could THAT be the source of the odor????  Considering you dump dish soap and so on into the gray tank.... You would not think it would stink.. but.. Well.. Check it out.

Unit is a used 2012.  Not running exhaust fan.  Not getting any smell from bathroom sink drain nor shower drain.  If it is poop pyramids, how do you break them up?

I have zero experience with a poop pyramid in an RV but I have many years experience with poop pyramids in my cottage outhouse, and the answer to dealing with it is to smash it up. In the outhouse I just use a stick to break it up and flatten the mound. I imagine in an RV the technique is similar.

clockdrfla said:

Unit is a used 2012.  Not running exhaust fan.  Not getting any smell from bathroom sink drain nor shower drain.  If it is poop pyramids, how do you break them up?

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Lots of water and many dumps.
They also sell a flusher you put on the end of a hose and run it down the toilet. I've never used one but they say it's very effective. Here's a ling to the one which is flexible in case you have a couple of 45 degree angles before it goes into the tank. They also have a rigid one if you have a straight shot.  If you do have a straight shot, you should be able to open the toilet valve with the water shut off and you should see the bottom of the tank. 

https://www.amazon.com/Camco-40074-Flexible-Swivel-Shutoff/dp/B0006IX7YC/ref=sr_1_5?ie=UTF8&qid=1519672382&sr=8-5&keywords=rv+black+tank+flush

We bought a Sun Joe power washer and an attachment which we used on our black and grey tanks.  That power washer had the right psi to use with the jetter tool.  We have only had our TT for 2 years and empty tanks at least once a week and use plenty of water  so we were surprised at the gunk  that came out. The link to hose attachment on Amazon is below...

Tank cleaning would have cost $175.  The pressure washer and hose was aaround $200 and we can use it as often as required.

https://www.amazon.com/Joe-SPX-PCH25-25-Foot-Cleaning-Pressure/dp/B01E0DPXFY

Before you assume it is a poop pyramid or the TP pyramid I once had, turn off the water and open the flush drain to see if you can see directly down into the tank.  I have a 2012 Fleetwood, and while there is a small bend in the drain pipe, I can see the bottom of my black tank through the toilet. 

I broke up my TP pyramid by adding half a tank of water, stirring with a stick, and then dumping.  (Make sure stick will not break.)  It did not clear the first time, so I added more water, stirred, and then drove around a deserted road, making sudden stops and doing some swerving.  (Important to choose a deserted road so no one would think I was a drunk RV driver.) 

Also important is to always put at least a gallon of water into your tank whenever you dump it.  The problem is that a lot of people drive around with an empty tank but then park when it is full.  My opinion is that agitation is needed sometimes.

By the way, I dump my black tank every 3-5 days, even though I travel solo because i add a lot of water with each flush.  Flushing the toilet is NOT the place to conserve water.  If you are going really skimpy on flushes, which I suspect because you are dumping it only once a week with two people, you may have a concentrated mess down there.  Adequate water helps keep the odor down, and mine never smells at all.

However, does your Fleetwood have an outside flusher?  If so, attach your hose to the connection when you dump and turn on the water to let it clean the tank.  Even though the instruction booklet said not to close the valve while flushing, I close it to let the tank get some water in it (2-3 minutes tops) and then let it dump.  Do this two or three times at dumps when I can.