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daledevon

Best Holding Tank Chemicals

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Probably going to get a wide range of answers to this one.

My response is that there is NOTHING you can/should do to make a black or gray tank "smell good". There are NOT septic tanks where you expect to hold contents for weeks or months.

All RV's are designed to isolate the smell of/in those tanks from the RV interior. If you smell holding tank odors inside the RV, I would address THAT-- not try to make tank contents smell good. Keep the odors out of the motorhome interior.

Basically, that means that there needs to be more atmospheric pressure in the RV than in the tanks.

Turn on a vent fan (i.e. vacuum in the bathroom) with the toilet valve open and the reverse happens. Drive with windows open and the reverse can happen. Your goal is to maximize interior pressure and minimize pressure in the tank.

There are a number of devices that reduce pressure in the tank. Most are based on the venturi effect on the tank roof vents. A good place to start.

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I'm not having problems, just looking to avoid them. There are so many products it's hard to know the best. I watched some youtube videos, but they seem to be from the mfg. Am I overthinking this?

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I hardly ever add chemicals to the holding tanks, sometimes my wife adds a little, not even the recommended amount on the package.

As Brett said a good venturi on the stack is the best place to start. Keeping the tanks reasonably clean, ie., back washing them on a regular basis. Also while camped, even on full sewer hookup, I keep my tank valves closed, then release them daily, black tank first, then with that valve open, I then release the gray water, letting the gray backflow into the black tank.

Remember they are holding tanks, not septic. I had a fellow RV'er next to me in a campground that allowed the tank valves to be left open. He had about eight people with him, and the black tank retained too many solids, he spent the largest part of one of those precious days unplugging the mess.

But if you think any special brand smells better than others, that would be the choice that I would go with.

Happy camping,

Kay

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Dale,

I have used several different types, liquid and powder. I have found that if you have an elbow in your toilet drain to the tank that powder types don't deposit into the tank itself as quickly. There have been times when you accidentally run out and have to go to a neighbor to get what they have and it to me is a test to see how that product works. Only to go back and use the one that is tried and proven to work the best, by me.

I use Thetford Aqua-Kem Liquid. Its 100% bio-degradable and breaks the solids down and controls odor very well. An 8 oz. bottle is recommended for a 40 gallon tank. I have a larger tank and dump it before heading home, then treat the tank and leave it ready for the next trip. You can find it at Wal-Mart or Camping World and just about any camping supply store.

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Thetford Aqua Chem is what we use. The old formaldehyde formulas seem to be long gone. We have no odor ever by the way. Maybe Tiffin plumbed it right on my unit. I keep my black water valve closed as has been mentioned and close the gray water valve a day before an anticipated dump of the black. As most probably do, we have the hookup for a black tank flush. We also keep a small trash can next to the throne for unnecessary tissue to be disposed of.

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Everyone has their own way of handling their waste water tanks. After living full time for almost ten years we adopted the following procedures as our routine for waster water.

We treat the black water tank regularly. Our 40 gallon tank will last the two of us for about two weeks. Unless travel plans necessitate dumping before the tank is near full, we'll go for 10 to 12 days before dumping the black water. It isn't a septic tank but with that holding time I think it helps to treat the tank to reduce odors. Even flushing will allow some odor to escape the tank into the interior of the motor home. We use "5 Star Happy Camper." It's a product that I bought at a rally many years ago. A pair of 40 ounce containers will last us all summer. It is a dry powder and we've found it very effective. It is available in a variety of package sizes. When we were full time we would purchase several years supply and store the excess in the storage shed on our winter campsite. Each year we would fill two 40 oz. containers when we left for the summer. It an easy to store, a single container or two will last you for a long time. As a bulk product, you don't have a lot of containers to deal with. The cost is very reasonable. If you can't find a dealer at a rally, it can be ordered on-line.

The gray water tank sometimes causes a problem, usually when our washer/dryer hasn't been used for a while. If the trap in a drain goes dry then the odor from the gray water will feed back into the motor home. It can smell almost as bad as the black water tank. Putting water down the drain to fill the trap will once again establish the seal and prevent odors. We occasionally add some of the Happy Camper treatment to help break down the build-up of food in the gray water tank. We always do that when we are on the road so the mixture will slosh around while we drive, then empty immediately after parking and hooking up.

When hooked up to a sewer our gray water tank is always open until the time for dumping the black water tank is near. Then we'll close the gray water and build up a supply for flushing the dump hose.

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Dale,

I have on both vent stacks venturies. They swival and are always turned into the wind when moving or parked. This causes a vortex behind the unit drawing the oders out of the tanks. I got them at Camping World.

As Brett said if you have the oder in the coach look for the cause. A good spray and vent fans work well, however turn them off before flushing.

Herman

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Dale,

We use the drop in pouches, which ever seem to be the cheapest. They all seem to perform equally.

Our old coach had severe interior odors from the black tank, strong enough that the small fan in bathroom couldn't keep up. I started to look into why and discovered that Coachmen had the black and gray tank vents connected to a "Y" in the wall and a single roof vent. Upon further discovery none of the fittings on the plastic pipe were glued above the floor level, just press fitted. Rather than opening the walls the rest of the way to fix I tried the same gadget Herman has and it solved our problems.

The only problem I had with the swivel vent was when we covered the unit it took a beating, I tried to protect it but I found replacing it every season was a routine I just had to face.

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Nothing is what you need. If you need a deodorizer, or smell either the deodorizer or the contents of the tank, something is amiss with your plumbing.

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We have had odors from the tanks in the past but it seemed to coincide with bumpy or rough conditions which I thought shook things up enough to have some odors escape the tanks. We always treat the tanks with either bleach or some detergent.

I think it helps but can still notice odors when on rough roads.

I believe their could be a vent problem with maybe a leaking check valve or vent cap somewhere that's not working properly.

I am installing the 360 Siphon vent cap this weekend if all goes as planned.

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We use the drop in pouches and have never had a problem with the black tank. What we have had problems with is a continuous smell from under the sinks. I don't have roof vents for each sink I have air admittance valves at each location.

I had never heard of these but a friend kept telling me it had to be located close to each drain location. I looked but could never see anything like that. Finally I was able to locate these by feeling around under each location. I replaced 3 of them and that took care of most of the problem.

Sometimes we still have an odor from around the washing machine. I'm sure there is another valve behind it but that is a major job. I'm leaving it alone till my wife makes me change it. I'm probably the only one that had never heard of these valves but I hope this helps someone.

They are only $7 at Lowes.

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Thanks guys for the idea on the vent cap. That was gonna be my next step to look at. I had seen some posts earlier about this vent cap and that's how I heard about the 360 siphon vent also. It appears our odor has been originating somewhere in the pocket door to the bedroom.

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Our old coach had a serious black tank odor problem, I think it was caused by the black and gray tank sharing a vent. I installed the 360 siphon and it cured ALL of the odor from the black tank after that.

The only problem I had was the plastic on these does not handle UV and NE winters very well and I would find myself replacing them every year. I eventually painted the last one and it was still good after 2 years.

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Our old coach had a serious black tank odor problem, I think it was caused by the black and gray tank sharing a vent. I installed the 360 siphon and it cured ALL of the odor from the black tank after that.

The only problem I had was the plastic on these does not handle UV and NE winters very well and I would find myself replacing them every year. I eventually painted the last one and it was still good after 2 years.

What kind of paint do you think would bond with the polycarbonate material and hold up the best? Would an exterior spray like Rustoleum bond with the material ?

Also I had seen a you tube video about a 360 Siphon that was taller and called a " Hi-Top ". Has anyone ever seen them and know where to find them?

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At the time I went to my local hardware store and asked what paint to use. I can't remember what it was.

Do you mean the "Roof mount 360 Siphon"?

If so I have two at home I have not yet installed, I like the simplicity of this design and the low profile stance it has. I bought them right after we bought this coach and have not found a need for them so I have not installed them as of yet.

My only concern is the snow here pressing weight onto the top, they look flimsy.

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Like Hermann, I have the 360, started using them in 02'.

Chemicals are expensive and heavy. Also, they don't solve the problem...hate the smell! :angry:

Wish they would come with the coach...that's another pipe dream!

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I don't use chemicals and I don't use any special paper. Never had a problem. If the valve in the bottom of the toilet won't hold water it is letting fumes/oder from the tank to enter the coach.

Bill

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