Close Encounters of the Odoriferous Kind

We recently spent 35 days away from our home dock. It was part vacation and part test run. Testing systems, ourselves and learning a LOT about our boat.

One of the more surprising issues we ran into was the, ahem, noticeable smell from the holding tank vent with each flush. We’re on a weekly pump out at home, had replaced the vent last year with a larger one and use NoFlex on the regular and frankly so we never really noticed this issue until this trip. Nobody’s wants to be “that boat” in the anchorage or worse, on the dock so we needed a fix.

Upon our return I read up in this forum about installing a tank aerator using some tubing, pvc and an aquarium pump.

I’m happy to report that within 48 hours of installation this system resolved the issue completely. All in I think the bits and pieces cost less than two cans of NoFlex.

Highly recommend installing one and so thankful to this group for teaching me how to DIY this solution.

How is this installed in the tank?

It will absolutely work. I have put air bubblers in 2 boats and they worked great.

I'm glad to see this info spread. I have had great success with our bubbler and encourage others experiencing holding tank smell issues that have tried other fixes to consider it. The method of installing it i your tank will depend on your individual situation and whether fittings are available to use or you need to install one. There are fittings available to easily add a fitting to an existing tank but I havent used them.

Here's the link to what I did. Only change is I have replaced the copper tube with PVC. I'd be interested if anyone finds an adjustable timer that works for them.
https://dkloeber.wixsite.com/bacchus/projects-pg-2

Bacchus said:

Here's the link to what I did. Only change is I have replaced the copper tube with PVC. I'd be interested if anyone finds an adjustable timer that works for them.
https://dkloeber.wixsite.com/bacchus/projects-pg-2

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The mfr of that air pump claims less than half an amp at 12 volts, so there are a number of programmable timers on the market that should handle it. Most these days can retain programming for more than a month of power being shut off, with an internal battery. I use one for a 12 volt low volume water circulating pump at home.

They also make relays that can handle up to 30 amps/12V that can in turn be controlled by these programmable timers.

Look at solar supply houses like Backwoods or Solaris.

lwarden said:

How is this installed in the tank?

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In my case I had an unused bunged 1-1/4" fitting in the top of the tank and fit up PVC fittings to fit inside a short section of hose. Two hose camps and voila!

The "wand" is vertical in my installation and was cut to end about 1" shy of the tank bottom. I know others have installed "L" shaped wands where the entire bubbling system is submerged. So far for me there doesnt seem to be a need to be submerged....just adding air to the tank made a huge difference.

Alaskaflyer said:

The mfr of that air pump claims less than half an amp at 12 volts, so there are a number of programmable timers on the market that should handle it. Most these days can retain programming for more than a month of power being shut off, with an internal battery. I use one for a 12 volt low volume water circulating pump at home.

They also make relays that can handle up to 30 amps/12V that can in turn be controlled by these programmable timers.

Look at solar supply houses like Backwoods or Solaris.

Click to expand...

My 12V timer just arrived from Amazon so I'll be installing today. Althought the pump is fairly quite we've been switching it off at the panel at night. Nicer to have this on a timer.

One note on power...I turned it on while looking at our BMK meeter and the amaperage draw didn't change at all.

Airstream345 said:

The "wand" is vertical in my installation and was cut to end about 1" shy of the tank bottom. I know others have installed "L" shaped wands where the entire bubbling system is submerged. So far for me there doesnt seem to be a need to be submerged....just adding air to the tank made a huge difference.

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I did an asymmetric "T" configuration. Works great but likely way overkill. Your system should work just fine.

From Airstream's experience, I wonder if just a simple supplied air inlet at the top of the tank without all the hardware inserted in there would be sufficient?

Going from an anaerobic system to an aerobic system is a huge difference. If it is operating correctly any smell should be something like freshly turned earth.

rgano said:

From Airstream's experience, I wonder if just a simple supplied air inlet at the top of the tank without all the hardware inserted in there would be sufficient?

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I think it likely would. After all, just increasing ventilation in a tank will often solve the problem.



Just a guess, but I think the agitation of the bubbles through the tank contents would not only increase the O2 content, but also help keep the tank contents circulating and possibly reduce sludge formation. However, that is a completely uneducated guess. As such, it is likely wrong.

rgano said:

From Airstream's experience, I wonder if just a simple supplied air inlet at the top of the tank without all the hardware inserted in there would be sufficient?

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I'm kind of with Dave.
I had the fitting available at bottom of the tank so bubbling was easy. My thought is even with any fitting at top adding the dip tube isn't much more difficult than not. I did no experimenting to try to quantify how little would work. I was eventually able to change my vent to a more direct but not shorter run. I am guessing that a timer with maybe 25% on time would work OK but just a guess. I dont hear the pump unless in the ER but I do hear the bubbling faintly in evening when things are quiet.
The admiral states clearly... its working well dont change anything. We still are using NoFlex but plan to switch to sodium percarbonate when the supply runs out.

I'd agree. Upon install the tank had just been emptied and things cleared up within 48 hours.