Holding tank chemicals

Impaler

Impaler

Well-Known Member
Joined
17 Feb 2004
Messages
570
Location
NE Scotland
Visit site
Hello,

My new boat has come with a holding tank which I believe is now compulsory on new builds.

I have no experience of these and was wondering if one should put in some sort of chemical such as you would in a porta potti. Or is it best just to flush them out with seawater as soon as possible after use ?

I see that Tek-Tanks sell some chemicals but I'm not sure if they'd cause any side effects.

Thanks.
 
If it's pong you're worried about, a well-designed and maintained holding tank isn't particularly smelly. A problem arises if there's insufficient air getting into the tank, which leads to anaerobic decay, which is the smelly sort (hydrogen sulphide and that sort of stuff). You can even buy additive packages of 'good' bacteria to help keep things sweet. On the whole, though, most folk don't bother, with that or chemical additives. Indiscriminately chucking harmful chemicals in the sea probably isn't a great idea, anyway.
 
macd said:
Indiscriminately chucking harmful chemicals in the sea probably isn't a great idea, anyway.
Click to expand...

+1

Apparently a serious problem in some parts of the US, where lots of people do put chemicals in their tanks.

Better to keep it all natural.

In most places in the UK you can probably leave it open a lot of the time anyway, flushing straight through. Then if you do go into an enclosed marina basin or the sort of nice bay or beach where people might swim, just keep it closed while in there and open up after you've left and got a reasonable distance from the coast.

Pete
 
^agreed.

When I'm in my berth and prepping for a sail where I know I'll be a suitable distance offshore I'll fill the holding tanks with fresh water from the dock hosepipe, then dump the lot when in a suitable area. Gives the tank a good flushing through :)
 
Lumping all chemicals together, from sugar to arsenic, is rhetorically pointless to me. A hollow statement.

I am from the US, have studied the issue in depth (environmental engineer and writer), and I have never heard of head chemicals being implicated in anything. Please supply back-up. That would be very interesting to me.

There are 3 classes of chemicals:
* Antiseptics. These are either very alkaline contain formaldehyde. I would certainly avoid formaldahyde (carcinogen). These are out of favor and are virtually off the market. They can also be hard on the head. Same with most toilet cleaners.
* Nitrate-based. These provide an alternative oxygen source to bacteria. Odor Los is a leading Euro brand.
* Culture based. Bugs or more properly, spores. These often contain nitrate as well.

The latter two classes can be very helpful with odor and will help your hoses last longer (they reduce aggressive sulfides). But they aren't strictly needed. They are very helpful for people who do not pump out regularly. Easier too.
 
No trace of anything called Odor Los on Amazon or E-Bay or the on-line chandlers in either France or the UK. I use Aqua-Kem Blue now and then, sending a good dollop up to the tank or Aqua-Kem tank cleaner in from the deck filler maybe once a month. I've also tried white wine vinegar which someone once recommended somewhere. Don't get any smelly problems ... :encouragement:
 
I think a lot will depend on your pattern of usage. We are marina dwellers, so the heads rarely gets used - and, when it does, almost exclusively for urine. I generally leave the holding tank drain open - it's a tidal marina, so an occasional half pint of pee is not too harmful. The only times that the heads is asked to handle solid waste is while we are at sea, or occasionally in the marina in the depths of winter in the middle of a stormy night. At sea, we leave the heads drain open and it flushes straight out. In bad weather in the marina, we may close the drain valve in which case we may be holding the contents for a few days - under those circumstances I will add a shot of one of the enzyme based treatments to keep things fresh and avoid the buildup of a solid blockage at the bottom. If there is a pump-out in the marina, we will use it every few days, otherwise we'll nip out to open water to dump it.
 
I find Elsan Blue good for keeping the toilet free of smells. Much more potent than the slightly cheaper own brand caravan stuff we used last year. Like others our toilet use is pee only. Never had and odour from tank.
 
Kingfisher 3 said:
No trace of anything called Odor Los on Amazon or E-Bay or the on-line chandlers in either France or the UK. I use Aqua-Kem Blue now and then, sending a good dollop up to the tank or Aqua-Kem tank cleaner in from the deck filler maybe once a month. I've also tried white wine vinegar which someone once recommended somewhere. Don't get any smelly problems ... :encouragement:
Click to expand...
Try UK Googling Odourloss and/or Odourlos (the spelling is inconsistent, I think it's aka Odorlos elsewhere)
 
Seawater is incredibly good at cleaning biological stuff for the most part. A soak in seawater for soiled clothes will almost get them clean, and is essential for blood spills if you want to avoid stains. The only real concern for tanks is if they are steel, like mine, when you need to avoid leaving urine in contact for more than a few days, three according to the instructions that came with mine.
 
PeterBoater said:
Try UK Googling Odourloss and/or Odourlos (the spelling is inconsistent, I think it's aka Odorlos elsewhere)
Click to expand...

Sorry for the bad spelling.

I would not touch Aquakem Blue or Elsan Blue with a 10-foot pole. Formaldehyde is a suspected carcinogen and is certainly quite toxic. They should take it off the market. Read your MSDSs!
https://www.campingworld.com/images/includes/productSpecs/Aqua%20Kem%20MSDS.pdf
http://www.partinfo.co.uk/files/Elsan%20Blue%20toilet%20fluid_SDS_rev%206.pdf

Odorlos is basically fertilizer, but is very effective. Many brands make variations (I mostly know US brands). Nitrate is the key.
http://www.yara.fr/images/5633_ODORLOS_Dry_tcm380-70870.pdf
 
Last edited:
thinwater said:
I would not touch Aquakem Blue or Elsan Blue with a 10-foot pole. Formaldehyde is a suspected carcinogen and is certainly quite toxic. They should take it off the market.
Click to expand...

It's for putting down the bog not for drinking.
Wearing gloves when handling it is recommended.
 
MartynG said:
It's for putting down the bog not for drinking.
Wearing gloves when handling it is recommended.
Click to expand...

Obviously, but if you look at the vapor exposure limits, they may actually be difficult to meet.

But more to the point, they contain hazardous chemicals that do not work as well the the nitrate approach, so why would I bother? Formaldehyde is also rough on joker valves and other elastomers. I am a chemical engineer and do not fear chemicals, but I have little used for stuff that doesn't work.

I have done side-by-side testing of many formulations for magazine articles. This is not anecdotal. It is also why I had this information available, off the top of my head.
https://www.practical-sailor.com/issues/37_14/features/solutions_stinky_holding_tank_10714-1.html
 
Most suppliers of chemical toilet fluids offer both a blue and a green version, the green being more environmentally friendly and many of the blues now do not contain formaldehyde though many do so read the labels. Many motorhomers now use bio washing liquids instead on the grounds of both economy and the environment. There is also a device called SOG which draws air through the toilet cassette each time it is used to maintain aerobic decay. I suspect some one with a creative mind could adapt this to work with a marine toilet. One of the reasons motorhomers are interested in the impact of toilet chemicals is many rural bio decomposition in their sewage treatment and many if not all blue chemicals in use harm this process. Green toilet chemicals are however OK for this process as are detergents
 
Scala said:
Martyn, don't fret I think thinwater is an American person. They as a race think that killing 10000+ of their own citizens every year with guns that they have the "right to bear" is fine. So a few chemicals that keep your bog clean is obviously to be denigrated mightily. I may have got the essence of this argument wrong.
Click to expand...

Yes, you did, by a mile. I didn't vote for Trump. I'm embarrassed by how many did. But this discussion will take us way off topic!

Honest, try Odorlos and other nitrate-based formulas, not because they are green, but because they really do work better. Not instantly, but over a few days. I don't think you will find a person that has tested or even used both that will agree that antiseptic-type treatments are better. Just try it.
 
I'm still missing the point of why you need to use the chemicals at all, whether green or not. Neither of the yachts I have owned with holding tanks has been smelly (one was in Turkey where you might expect the heat to have made it pong a bit), so it just seems like spending money to pour something into the sea.........
 
You must log in or register to reply here.

Share this page

Top