Smelly Holding Tank

[Beauregw]

I've got a 1985 43' motor yacht. The heads are Raritan crowns- the vac-u-flush system has been removed. I've owned it for 4 years, and from the first day I used it, there has been a horrible smell coming from the holding tank vent whenever we flushed. I tried all kinds of holding tank chemicals, and nothing worked. I then had all of the hoses replaced. I'm told the hoses were clogged like my arteries. I have since treated the holding tank several times with pool shock, which has helped a bit, but the problem is still there, leading me to believe that the problem is an accumulation in the tank. Since there's no way to clean it mechanically, I'm wondering if anyone knows of a chemical (acid) treatment that might boil it out.

[Bob Bradley]

I have had the same smell problem when the tank on my '79 43C is getting full. There is less air in the tank, so a flush pushes out more concentrated smell. When the tank is less than half full, it is not noticable. Are you certain that the tank is being emptied completely when you have it pumped out? Mine is (I think) a 165 gallon tank, and it takes about 10 minutes to have it pumped when it is nearly full. I've had the pump guy ask me if my valves are set open to the outside, as he thought he was pumping in raw sea water rather than holding tank effluent. By the way, most marine toilet pros warn against using chlorine, as it can break down hose walls, and also stops the natural process by which the "stuff" in the tank breaks down. Apparently it kills the bacteria that break down the waste.
Bob

[PascalG]

it's normal for smells to come out after a flush since air is expelled. depending on vent location and prevailing wind, it can be a problem.

you can add a vent filter in the line, which helps filter the air out. problem is that they clog easily if wet (as if you over fill trhe tank). they need to be changed every 2 or 3 years. avail at west marine.

as bob said, chloring is no good. it kills the "good" bacteria which breaks down waste and absorb soem of the gases. Flush a few times and then try the holding tnak treatmetn. I've had good luck with odorloss

pascal
miami, fl
1970 53MY

[67H34C]

I WAS CONSIDERING RID-X. BUY FROM GROCERY STORE OR HOME DEPOT. OR BAKERS YEAST, SAME THING. IT IS BACTERIA TO EAT UP THE STUFF, ALSO CAN CONTROLL THE SMELL, I THINK. GIVE IT A TRY, VERY CHEEP FIX.

LET ME KNOW IF IT WORKS, WE HAVE NOT USED THE TANK IN OUR BOAT YET, JUST PRUCHASED LAST YEAR BUT WHEN WE RE PLUMB IT I PLAN ON TRYING THIS.

STEVE HIERHOLZER
SHIERH@AOL.COM

[dshuman]

They have it at many marinas, Boaters World, etc. I use it all the time in the concentration recommended on the bottle and even when I had to open up my tank top pipes to fix it, there was almost no smell at all. I was amazed.

[ronbecky]

There is an article in Passagemaker magazine Jan 2003 that deals with this problem. The author installed a bubbler system (as in aquariums) in the tank and by pumping air into the tank, eliminates all odors from venting. You can put this together by visiting Wal Mart for all the supplies. Groco has the same system called "Sweet Tank" that has all the parts needed to install but is kinda pricey. Claims there is no need for any chemicals to be added. In fact he states that adding chemicals adds to the conditions contributing to gassing.

[spartonboat1]

Do a full pump out. Pull the plug from the top of the pumpout pipe and using the good old unbent clothes hanger validate that your pumpout pipe is 1) Not brass- if white plastic then probably OK, and 2) If brass, it maybe rotted out 1/2-2/3 the way down and you are not getting a full pump out.

If you check after a pumpout, only an inch or so of flush out water should remain.

I have an old 1972 43' and had to remove all the piping hardware and do a total flush with Clorox to remove all old accumulation. Cured any issues...

No ice on Great Lakes yet...

[Nonchalant1]

The stuff that smells is created in an anerobic tank, where there is not enough oxygen. Normal septic processes (aerobic) don't smell that much. The tank bubbler will help, as will larger vent lines or even cross ventilation (vent lines into two areas of the tank top).

We've used "Odorlos" (mentioned above) for years and have almost no tank smell at all, including when I had to take the bronze fittings out of the tank to restore the pumpout pipe and add a tank gauge.

[Trojan]

When I find a boat with build up in the holding tank.I dump in a large amount of bleach in the tank a few days before a pump out and go for a short run to mix it around.This loosens the crud on the bottom of the tank and sides.I don't worry about the controlling longterm smell,It's going to be pumped out in a few days anyway.Unless you leave your tank with with sludge in it for a long period of time.You have no or very little septic action.It's not a septic tank,it's a holding tank.Deal with killing the smell and pump out more.Make sure your outside vents are working.Spiders love these vents and make sure your pump out tube reaches the bottom.Bill

[MORNING STAR]

Peggy Hall is the expert on holding tanks. She covers the subject you guys are discussing and has written a book on the subject. I sent her an e-mail and asked her to respond to you.

Her e-mail is peghall@sbcglobal.net if you want to contact her directly.

Dennis
Morning Star