Cleaning Holding Tank

I know this has been discussed, but I was unable to locate anything using the search option (operator error, I'm sure). When down in the ER chasing corroded battery terminals, I definately smelled the holdihg tank, more noticable than before, and I am guessing probably from lack of use during the last 6 months. Suggesitons on filling with something and pumping out a few times to alleviate this? Water and vinegar? The hoses are all newer and I don't think are the culprit. Breahter is OK too.

On the plus side, while digging around doiwn there, I went through the spare parts box left by the previous owner, and found hidden in the bottom two Racor vaccuum gauges that had nver been installed, SCORE!

I had this problem before but it was not the holding tank that was the culprit, it was the sanitation lines. I could be wrong but your holding tank should not produce an odor unless it was opened.

Check your lines by rubbing your hand on it and smelling your hand. If it smells like doodoo, your hoses are permeated and in need of replacement. If the hoses are good, you might have a small leak somewhere.

An easy way to check the hoses and tank for odor is to take a dry paper towel and rub a section of hose then smell the paper towel. If you have odor on the paper towel it is time to change the hose. Particularly test the low spots or areas that liquids could be sitting. If you have any break though, cleaning the tank or hose won't help, time to replace, although the cleaning will help keep things cleaner during replacement. Marine Sanitation in Seattle taught me this one.

I'll check the hoses. The toiltes are newer and have new hose. The pump out line is older and black rubber type. That maybe the culprit.

Unless your tank is leaking--- a definite possibility if it's a metal tank--- the culprit is almost always a permeated hose. Once a hose has permeated there's really nothing you can do about it except-----

Read the current thread on sanitation hoses where Carl (Delfin) has comments on his use of a product called PetroWrap (I think) to wrap a permeated hose and I relayed advice from Peggie Hall on using Saran Wrap for the same purpose. Peggie never advocated the Saran Wrap as a permanent fix. And of course, whether you can use either of these techniques in your situation depends on how easy it is to access the hose to thoroughly wrap something around it.

If you can replace the hose with PVC, that will end the permeation problem permanently. If you use PVC, as we have in our boat, make sure to have flexible couplings at each end. If the PVC is rigidly connected, vibration and stress will eventually crack it or break a fitting.

Putting stuff--- vinegar, etc.--- into a system may help prevent permeation to start, but once it's happened, the smell is in the hose material itself and nothing you run through the hose will reverse it.

Delete duplicate post.

Max Simmons said:

Suggesitons on filling with something and pumping out a few times to alleviate this?

The hoses are all newer and I don't think are the culprit. .

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Sodium hydroxide (lye - Drano) will clean the tank, remove the oils and fats, and deposits. Either pour liquid or crystals directly into the pumped out tank and fill with water, let it sit. Flush it out, repeat, stick a hose down into the tank to wash the sides well and repeat.

This will sterilize it and clean it thoroughly. Be very careful though, wear chemical protection gloves, no exposed skin, and the best eye protection you can get when hosing down.

Unless the tank is made of really flimsy material or is leaking I would be surprised if the tank itself has permeated and is the source of the smell. Hoses are the most common cause, as noted by others above. A vent could be the source, as well, or a seeping fitting. But the hoses leading to and from the tank generally prove to be the problem.

Cleaning the inside of the tank certainly won't hurt anything and you never know, it might solve the problem. But don't be too surprised if after you do this you find the odor is still there.

Marin said:

I would be surprised if the tank itself has permeated and is the source of the smell.

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This is the problem with forums like this ... the guy asked how to clean the tank. So far he has only received advice on where the smell might come from.

RickB said:

This is the problem with forums like this ... the guy asked how to clean the tank. So far he has only received advice on where the smell might come from.

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No, someone suggested pouring caustic chemicals into it. edit: Oh wait, that was you.

Here's how I cleaned mine. I cut a hole in the top of the holding tank to match a standard screw in gasketed cover. Six inches, I believe it was, but buy the cover first, then cut the hole.

With the hole cut, I was able to use a garden hose and nozzle to dislodge much of what was stuck to the sides and bottom of the tank.

After pumping the liquid out of the tank, I used a brush and a scraper to loosen the rest of the solids amd I pumped and rinsed. Then I screwed the cover tight.

Why clean a holding tank when it will just fill with s**t again? I have a gauge that uses plates stuck to the sides of the tank and the gauge reads "full" if there's s**t stuck to the sides.

BTW: I agree with some of the other posts, the tank is unlikely to be the source of the smell. Peggy Hall's test for permeated hoses is to soak a clean white rag in hot water, wring it out, wrap it around the hose to be tested, leave it in place for a few minutes, then remove it and smell it.

Here is a process that is recommended for RV's
https://sites.google.com/site/cbruni/

rwidman said:

... buy the cover first, then cut the hole.

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Now THAT is good advice.

Water softener, detergent and chlorine bleach. Sounds like it might work. If anyone tries it give us an update.

Forkliftt said:

Water softener, detergent and chlorine bleach. Sounds like it might work. If anyone tries it give us an update.

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It might, but I doubt it. That would be like putting the laundry in the washing machine but not tuning it on.

My 45 gal. translucent plastic tank has a 6"screw in plate on top once in a while I'll stay in a marina with inslip self pumpout. While there I pump out, then remove the cover and with a water hose and nozzle spray the insides of the tank well, then I'll pump it out again. This has worked well for me knocking the crud off of the walls, as already mentioned it won't do anything for permeated hoses.
Steve W.

Steve said:

My 45 gal. translucent plastic tank has a 6"screw in plate on top once in a while I'll stay in a marina with inslip self pumpout. While there I pump out, then remove the cover and with a water hose and nozzle spray the insides of the tank well, then I'll pump it out again. This has worked well for me knocking the crud off of the walls, as already mentioned it won't do anything for permeated hoses.
Steve W.

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I sometimes wish we had an access port on the holding tank. The boat was built with fuel tank and even water tank ports. The holding tank is original and fiberglass. I suppose one could be added?

If you can access the top of the tank probably you could cut a hole and install a Screw in Deckplate which is what is in mine.
Steve W

Steve said:

If you can access the top of the tank probably you could cut a hole and install a Screw in Deckplate which is what is in mine.
Steve W

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I did a google and Beckson makes a nice looking one. Think I'm gonna add one.

I'm sure chlorine bleach works well, the issue is that it is extremely damaging to the environment. Bleach would be okay for a pump out but not ok for dumping while at sea.

Taras said:

I'm sure chlorine bleach works well, the issue is that it is extremely damaging to the environment. Bleach would be okay for a pump out but not ok for dumping while at sea.

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From Wikipedia...

Risk Assessment Report (RAR) conducted by the European Union on sodium hypochlorite (bleach active ingerdient) conducted under Regulation EEC 793/93 concluded that this substance is safe for the environment in all its current, normal uses.[24] This is due to its high reactivity and instability. Disappearance of hypochlorite is practically immediate in the natural aquatic environment, reaching in a short time concentration as low as 10−22 μg/L or less in all emission scenarios. In addition, it was found that while volatile chlorine species may be relevant in some indoor scenarios, they have negligible impact in open environmental conditions. Further, the role of hypochlorite pollution is assumed as negligible in soils.

Taras said:

I'm sure chlorine bleach works well, the issue is that it is extremely damaging to the environment. Bleach would be okay for a pump out but not ok for dumping while at sea.

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Chlorine bleach will whiten organic stains and it will disinfect, but it does not "clean". For cleaning, you need some sort of soap or detergent.

Think about this - When you do the laundry and wash the white items, do you use just chlorine bleach or do you use detergent and add bleach?

The only legitimate use for chlorine bleach on a boat (unless you have a washer and dryer on the boat) is to chlorinate potable water that has not already been chlorinated (such as from a private well).

I use clorine bleach to whiten stains in gel coat/white vinyl, do hand laundry, sanitize surfaces, disinfect the bilge when sewage gets in there from changing a pump or hose, get mildew/mold stains out, whiten porcelain cookware, it puts a real shine in glassware,.....I have more just tired of typing...

Oh yeah...I just read someplace that you can addi to water tanks if you suspect the water source may not be up to snuff...

rwidman said:

For cleaning, you need some sort of soap or detergent.

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That is the bottom line on cleaning a holding tank. Bleach kills germs but it doesn't clean anything.

Sodium or potassium hydroxide lye, Drano, caustic soda ... whatever label it has is what works. It dissolves the crud then converts the oils and grease to soap that can be washed away with rinse water. It dilutes in discharge water and degrades quickly, just like bleach, and is environmentally safe.

When your drain clogs at home you don't put bleach down it and hope it clears the grease and hair do you?