A Tale of Two Holding Tanks

[Maine Sail]

The tanks:

Tank #1

In early December I yanked the sanitation system out of a customers boat due to the NASTIEST stench you can imagine. I HATE these jobs. The original factory hose was still in use and the boat was a 1987 making the tank and hoses 25 years old. Knowing his tank was a Ronco roto-molded tank, the black one pictured on top, and these tanks don't "odor permeate" I told the customer I would clean it, disinfect and re-install. I've done this before and never had an issue.

Well....... Beginning in early December I began cleaning the exterior of the tank, after plugging the tappings. First I sprayed the exterior with a 50/50 bleach solution and let it dry and evaporate in place. I came back the next day and the tank STILL STUNK so bad you could barely smell any bleach. I did this again, and here's what followed.

1: Second application of 50/50 bleach.... still stunk
2: Third application this time PURE bleach... still stunk
3: Physically washed exterior of the tank with SEVEN magic erasers and Simple Green...still stunk
4: Physically washed exterior of the tank with 3M Sharp Shooter industrial cleaner....still stunk
5: Filled a HUGE rubber maid container with 8 gallons of bleach and water. Filled interior of the tank with four gallons of bleach and water so it would sink in the bleaching tank. Left in bleaching tank solution for FOUR WEEKS..... Still stunk
6: Spayed tank with Pure Ayre and let dry, supposedly the finest odor eliminator on the planet....Still stunk
7: Sprayed tank with Pure Ayre and let dry... Still stunk
8: Spayed tank with Pure Ayre and let dry,....Still stunk
9: Spayed tank with Pure Ayre and let dry,....Still stunk
10: Used an ENTIRE $15.00 bottle of Pure Ayre, still stunk and gave up.
11: Ordered customer a new holding tank......
12: After nearly three months I drained the POTENT bleach out of the inside of the tank because I needed my tank plugs. IT STILL STINKS!!!!!!!!


Tank #2

Tank #2 came off our own boat last week day after being in service for 33 years. It is also a rotomolded tank made from supposedly the same material as tank #1. I suspect it was made by Kracor though the label is obscured, but the colors look just like a Kracor label..

To say the least I was expecting BAD THINGS especially seeing as this was a live-aboard world cruiser for five straight years..

I took the tank out, plugged the tappings and sprayed with a 50/50 bleach solution. Came back the next morning and NO STENCH?????

Not believing this I;

#1 Hit it again with a 50/50...No stink
#2 Washed it with magic erasers and 3M Sharp Shooter.... No stink
#3 Filled it with 6 gallons of bleach and the rest water, let sit for three days and just drained it. Even the insides now have NO STINK.......

I plan to hit it with Pure Ayre anyway before putting reinstalling the tank but it already has ZERO odor and I am damn picky when it comes to my boat....



So my questions to the masses & Peggy (if she's reading Ask All Sailors) are:

1- We've been told these types of holding tanks don't and can't odor permeate. If it did not, how can tank #1 STILL stink to high heaven after MONTHS of cleaning effort? Peggy has asked for proof of odor permeation for years and I am holding onto this tank just for her.

2- How can tank #2 NOT stink at all after being in worse service conditions for 8 years longer than tank #1?

3- How can there be this much variability in stench absorption in two rotomolded tanks supposedly made from the same material?

 

[Rick D]

Just Wonderin'

...if holding tank treatment products and practices could be the difference?
What would be interesting is to contact Ronco and ask their staff.

 

[RobG]

Same here

When I bought my E28 it had the same problem. I removed every bit of the sanitation system except the trough hulls for the vent and pump-out. The overboard discharge seacock was removed and the through hull capped off. The PHII cleaned up nicely.
While I tried very hard to clean up the holding tank, also a black Ronco, I had the same results as you and boy...what a disgusting job. I finally left the tank near my back yard shed where it would sit in the sun most of the day. Well...nature and UV should get rid of the smell right? After two months of smelling that bugger every time the house was down wind 100' away I'd had enough. New everything INCLUDING new tank.
I think RickD has it. How it was treated for those many years must have a lot to do with it.
Oh yeah, the the compartment the tank was/is in still smells. Even after lots of scrubbing and repeated dousing with Pure Ayre. It does seem to be fading with time though...slowly...

 

[captainpat]

That is puzzling if, in fact, the construction material is identical - and I don't THINK this has been ABSOLUTELY established based on what I read in your post. My suspicion would be that the material is not the same. The only other difference, other then shape, is the color. Hard to believe that would be a factor. It is POSSIBLE that some sort of agent was used in tank #1 that compromised its resistance to odor permeation. Maybe that agent had an effect on the black material and not the white? I'll be very interested in your follow up.

 

[Tim R.]

I pulled my tank from my '85 Ericson that was a Ronco roto-moulded tank and tried cleaning it similar to your efforts. I could not get rid of the smell.

Now I have a built into the hull FG tank. No smells yet after 15 years, 7 of those being full time live-aboard.

 

[Maine Sail]

...if holding tank treatment products and practices could be the difference?

Over 33 years and 25 years respectively I would suspect that the treatments changed often for both tanks and that in the end it should have mattered little if they are not supposed to "permeate" or absorb odor....

What would be interesting is to contact Ronco and ask their staff.

I did and... "They don't permeate."..... When I explained what I had been through that changed to "The odor could have attached to the tank." ....?????

 

[juslookin]

Roto Mold Poly

There are at least two types of polyethelyne that I know of used in roto mold situations, back in those days. The best of the two I am aware of is cross linked poly. Non cross linked material will permeate through the material. Cross linked material will not do this.

 

[tommays]

We use a LOT 1000 kilo plastic chemical totes (food grade) and i can assure you they both stain and retrain with age as the pours on the interior seem to open with age

 

[Benny17441]

If going through the trouble of removing holding tanks I think the most practical course of action would be to replace them. Would not want to have the boat laid up for weeks while trying to odorize an old tank which may have already exceeded its useful life. We don't lay up the boat for the winter down here. Certainly would not want to have to pull them out again in just a couple of years because they started to leak.

 

[Calif. Ted]

Maine, If I was your customer I'd have told you to order a new tank at step 2, your time is too valuable.
If you ever want a working vacation in California you got carte blanche to fix anything you don't like on my boat.

 

[Maine Sail]

Maine, If I was your customer I'd have told you to order a new tank at step 2, your time is too valuable.
If you ever want a working vacation in California you got carte blanche to fix anything you don't like on my boat.

I charged him for 3/4 of an hour for all that. Tank was in my barn and it did not take much time to do that stuff. Sniff, spray etc.... I had more into it than 45 minutes but I told him I could disinfect it, and couldn't.. Not really his issue + he had to buy a new tank so we kind of split the difference. In the future when I come across a Ronco I will suggest new..

Both of these tanks are cross-linked polyethylene...

 

[RAD]

I went through the same with a holding tank but didn't spend to much time and decided to figure out how to get a larger tank in the same space and tripled my capacity and this was after changing hoses,Y valves and rebuilding the head

 

[FastOlson]

It's a Mystery

From the "for what it's worth" dept...
When I removed the '88 original Ronco black plastic holding tank from our boat it cleaned up with NO odor remaining at all. Matter of fact I sold it (cheap) to another boater and it's back in use now.
(I was reconfiguring the whole waste plumbing layout and increasing the capacity of the h.t., was the reason for getting rid of the old tank.)

So, there's gotta be some reason, having to do with the plastic material of those tanks, why one can permeate and another one does not.

Probably of no value to the discussion, but a couple of decades ago I bought and then had to return a new fresh water Krakor tank. It had an awful "burnt plastic" smell that would not clean up or go away. I was told by the vendor that the temperature has be exceedingly-carefully controlled during the roto-molding process and one possible failure can be "over cooking" which produces a signiture odor. Perhaps... maybe... there are more subtle temperature problems that result in long-term permeability -- and that even carefull attention to QC does not always catch this default.
Perhaps?
:cry:

Anyhow, that's just one SWAG, and hardly worth even one cent.

LB

 

[gettinthere]

Maybe it was the diet of the prior owner?

Seriously tho...perhaps the smelly tank was compromised by some home brew chemical treatment that etched the inside and allowed the permeation.
I pulled out a 25 year old bladder tank that did not permeate. But the exhaust hoses used for sanitation sure did!

 

[Scott T-Bird]

A topic that I follow with a great amount of interest!

I'd have to pull out the thru hulls to get my tank out of the small opening so I haven't tackled this project yet (except after watching the fine demonstration by MS on the strength of marelon thru-hulls, I am thinking of making this a new priority!).

I replaced the hoses and head long ago, but only after several years of rinsing with a light bleach periodially in the tank, has the odor finally dissipated. The compartment finally has far less smell as well. We never overnight on our boat so the head and holding tank have extemely light duty. The tank is normally empty or just a small amount of fresh water and a light amount of bleach.

It took a long time for the stench to dissipate and if we ever slept on the boat, it couldn't have been tolerated as long as we did.

 

[RobertLangdirect]

A difference between what we assume and what we nose.

. . . Both of these tanks are cross-linked polyethylene...

Maybe, consider -- both of these tanks are SUPPOSED TO BE cross-linked polyethylene. Besides the smell, there is a difference that makes this so.

Robert