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Which odor control product for holding tank urine

MikeWT

.
Sep 30, 2018
5
Beneteau 343 Bristol
What’s the best product for a holding tank now used for “#1” only?

We had been using Raritan CP and Raritan KO per advice in Peggy Hall’s book.

Mid last season year we switched to Zaal No Flex based on a review in Practical Sailor (and still used Raritan CP as well)

This year we started using Nilodor Urine Digester based on anew article in Practical Sailor and on a different theory that for just urine it is better to limit growth / neutralize instead of promoting growth / activity as you would want with sewage including “#2”

We’re trying to achieve “zero smell” but continue to get some stink when head is flushed. Wondering which of these products is theoretically the best approach. - Is the urine digester a good idea for a holding tank or is it really only for composting toilets where 1 and 2 are completely separated?
- Should we go back to Raritan KO as defacto best and compatible with CP?
 
Jan 11, 2014
7,727
Sabre 362 113 Fair Haven, NY
If you are not using a freshwater flush, you will always have some odor due to the critters and stuff in the sea water that will die in the hose. Setting up the head to use freshwater to flush will reduce this odor.
 

MikeWT

.
Sep 30, 2018
5
Beneteau 343 Bristol
Ahh. Good point. I should have mentioned we use freshwater flush only. Disconnected salt water intake and replaced head and hoses a few years ago. Only the holding tank itself is “original” (2006).
 
Dec 2, 1997
8,086
- - LIttle Rock
If you are not using a freshwater flush, you will always have some odor due to the critters and stuff in the sea water that will die in the hose. Setting up the head to use freshwater to flush will reduce this odor.
I hope you aren't recommending "setting up" a sea water toilet to connect to the boat's fresh water plumbing because that's a big no-no and every toilet mfr warns against it because it cannot be done without risk of contaminating the fresh water supply. Rerouting the head intake to tee into the head sink drain line is the only safe way to provide fresh water to a sea water toilet (see the many discussions on sbo.com about how to do that).

It's important to know whether odor is emanating from the bowl (dead and decaying sea water organism trapped in the head intake line and channel in the rim of the bowl) or out the tank vent.

Whether the toilet flushes with sea water or fresh water, or whether only urine goes into the tank makes no difference in the holding tank...odor out the tank vent is the result of anaerobic conditions (vent doesn't provide enough oxygen) in the tank. There are a few tank products--Odorlos and No-Flex-- that can promote enough oxygen release from the waste to prevent odor out the vent...live bacteria products (Raritan KO is the most popular) cannot...they need aerobic conditions to work. A larger diameter, shorter, straight vent line and an open vent thru-hull to replace the standard "vent" thru-hull are necessary to provide enough air exchange. And btw...there is NO reason to avoid flushing solid waste...it's 75% water to begin with, breaks up going through a manual toilet or is macerated by an electric toilet, so dissolves very quickly in water...has NO impact on odor from the tank. So I can't see any advantage to using a "urine digester" in a holding tank. Btw, Mike...Raritan C.P. is NOT a TANK product. However in addition to being an outstanding bowl cleaner, it is the best sump and drain cleaner on the planet!

Odor from the bowl caused by dead and decaying sea organisms in the intake line, pump and channel in the rim of the bowl can only be prevented by flushing the sea water out of the system before the boat will sit. Easy enough to set up on most boats...see the discussions about re-routing the intake line to tee into the head sink drain. To rinse the sea water out the entire system--intake AND discharge--only requires closing the sink drain seacock, filling the sink with fresh water and flushing the toilet.

You can search the archives for all the posts on both these issues...instructions for doing both are included in my book (see link in my signature below).

--Peggie
 
Last edited:
Feb 14, 2014
5,622
Hunter 430 Waveland, MS
A cheap , per flush, neutralizer is...

ff1fd7c5-0e1f-413a-af24-21c1c862e403.f1c5d665aea3002c139c86acab5b8d3d.jpeg

Two Tablespoons [ coffee scoop] before the flush and watch the cleaning bubbles neutralize the Uric Acid.
Safer for Aluminum Hold tanks too.;)

We keep some and the scoop in a slider zip lock bag behind the toilet.
Jim...
 
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MikeWT

.
Sep 30, 2018
5
Beneteau 343 Bristol
Awesome. You’re the best. Thanks so much. I get it. You brought together a few pieces of info I just hadn’t correlated.

We will go back to using Noflex and won’t worry if someone needs to go #2 on occasion. Had thought about increasing vent line /outlet size (it is very small) but didn’t want to tackle that project yet.

I suppose we can keep using the Raritan CP just for toilet bowl cleaning after each weekend, but understand it doesn’t have “long term” benefit.

(It is a Raritan Marine Elegance electric flush, hooked up to fresh water only, no saltwater.)
 
Dec 2, 1997
8,086
- - LIttle Rock
I suppose we can keep using the Raritan CP just for toilet bowl cleaning after each weekend, but understand it doesn’t have “long term” benefit.
You don't have to use it ONLY for bowl cleaning...as I mentioned above it's a great shower sump and sink drain cleaner.

Raritan only markets their "C.P. Cleans Potties" as a bowl cleaner--and it is an excellent one. But it's also the best sump and drain cleaner on the planet. C.P. is a bio-enzymatic cleaner that not only destroys odor on contact, but the enzymes in it "eat" hair, soap scum, body oils, galley grease and all the stuff that clogs sumps and drains and makes 'em stinky. All you need to is put 2-3 oz down the shower drain when it can stand at least overnight...the enzymes need time to work. Then flush clean water through the sump. You can even let it remain in the sump for weeks, 'cuz although the enzymes exhaust themselves in 24 hours, there's nothing in C.P. that can harm anything.
To clean sink drains, close the seacock, then put about an ounce of C.P down the drain and fill the drain with water--again when it can stand at least overnight. That's it. The only jobs on a boat that require -0- manual labor.

Fwiw, C.P. is part of the product line my own company developed in the 1980s (K.O. is another one) and sold to Raritan in 1999, so I'm VERY familiar with them!

--Peggie
 
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Jan 11, 2014
7,727
Sabre 362 113 Fair Haven, NY
I hope you aren't recommending "setting up" a sea water toilet to connect to the boat's fresh water plumbing because that's a big no-no and every toilet mfr warns against it because it cannot be done without risk of contaminating the fresh water supply. Rerouting the head intake to tee into the head sink drain line is the only safe way to provide fresh water to a sea water toilet (see the many discussions on sbo.com about how to do that).
@Peggie Hall HeadMistress come on, you know me, would I really suggest something like that? :huh:
 
Dec 2, 1997
8,086
- - LIttle Rock
I know you, but not everyone who reads what we write does. I learned years ago that for every participant in a discussion forum, there can be hundreds of lurkers who never say a word, many of whom are total boating neophytes who don't know aft from stern, but think they want to learn. So I'm always very aware that I'm rarely talking to just one person.

--Peggie
 
Nov 22, 2011
959
Ericson 26-2 San Pedro, CA
I know you, but not everyone who reads what we write does. I learned years ago that for every participant in a discussion forum, there can be hundreds of lurkers who never say a word, many of whom are total boating neophytes who don't know aft from stern, but think they want to learn. So I'm always very aware that I'm rarely talking to just one person.

--Peggie
You mean their aft from their stern run aground?