Marine16 vs Wynns, diesel bug biocide

[wakey_wake]

I dose my tank with Marine 16 diesel bug treatment at the prevention level my only complaint so far is the price 💸

 

I noticed this one which sounds like it will do the same job, at least for prevention if not also as shock treatment,

 

https://www.amazon.co.uk/wynns-apos-Biocide-Algae-Bottle/dp/B00H7YJYCC/ Wynn's Fuel Biocide Against Algae Formation, 250 ml Bottle   £18.10

 

at 250ml for almost the price of Marine16 100ml.

 

Today I also learned that these things have a shelf life of 2~3 years, so "bigger bottle, better price" may be false economy.

 

Thoughts or experiences? Like a fire extinguisher, it is one of those things we don't generally test but we buy and hope it's going ok...

[Jen-in-Wellies]

Personal experience is one of those things thst is pretty useless in these sort of cases. 

I have never had diesel bug in the boat fuel system. Since diesel went FAME, I've preventative dosed it with Marine 16, when I occasionally remember to. I've not had diesel bug since. I've not had any goldfish in my diesel tank either, so Marine 16 definitely prevents diesel bug and goldfish in my experience.

[pearley]

As I have diesel stove I use a fair bit of Marine 16 so buy 1 litre bottles @ £51.95

[Tonka]

15 minutes ago, wakey_wake said:

I dose my tank with Marine 16 diesel bug treatment at the prevention level my only complaint so far is the price 💸

 

I noticed this one which sounds like it will do the same job, at least for prevention if not also as shock treatment,

 

https://www.amazon.co.uk/wynns-apos-Biocide-Algae-Bottle/dp/B00H7YJYCC/ Wynn's Fuel Biocide Against Algae Formation, 250 ml Bottle   £18.10

 

at 250ml for almost the price of Marine16 100ml.

 

Today I also learned that these things have a shelf life of 2~3 years, so "bigger bottle, better price" may be false economy.

 

Thoughts or experiences? Like a fire extinguisher, it is one of those things we don't generally test but we buy and hope it's going ok...

Where did you find the shelf life info? Because I used to have a larger bottle and as only filling up twice a year it lasted ages

[pearley]

AI suggests a shelf life of 24 months if kept at correct temperature 

[alias]

18 minutes ago, Tonka said:

Where did you find the shelf life info? Because I used to have a larger bottle and as only filling up twice a year it lasted ages

 

ISTR that my bottle has a "use by" date stamped on the bottom. 

[Momac]

I think marine 16 only recently added an expiry date. 

Sounds like a good marketing idea.

 

 

 

 

[Tonka]

44 minutes ago, Momac said:

I think marine 16 only recently added an expiry date. 

Sounds like a good marketing idea.

 

 

 

 

I was just thinking that I don't remember seeing an expiry date on it

[blackrose]

2 hours ago, wakey_wake said:

I noticed this one which sounds like it will do the same job, at least for prevention if not also as shock treatment,

 

 

 

That's the problem, they ALL sound like they do the same job, but the reality is they don't. Remember Fuel Set? Turns out it was useless. 

 

The reason Marine 16 became popular is because it was independently tested alongside about 5 other brands about 20 years ago and the results published in Practical Boat Owner. The results were quite varied with Marine 16 along with Grotmar? coming out on top.

 

 

[alias]

1 hour ago, Momac said:

I think marine 16 only recently added an expiry date. 

Sounds like a good marketing idea.

 

 

 

 

Can't remember exactly when I bought it, but it was the last couple of years and the expiry on it is this September I think.

[Tony Brooks]

36 minutes ago, blackrose said:

That's the problem, they ALL sound like they do the same job, but the reality is they don't. Remember Fuel Set? Turns out it was useless. 

 

Not as a demulsifier, which it was, but as far as being a biocide, I agree, useless. But as I remember it did not claim to be, just that it allowed water to drop out of the fuel to allow it to be removed via the tank drain, that all narrowboat have - not. No water and the bug finds it far more difficult to breed.

Edited April 16 by Tony Brooks

[blackrose]

35 minutes ago, Tony Brooks said:

 

Not as a demulsifier, which it was, but as far as being a biocide, I agree, useless. But as I remember it did not claim to be, just that it allowed water to drop out of the fuel to allow it to be removed via the tank drain, that all narrowboat have - not. No water and the bug finds it far more difficult to breed.

 

I might be wrong but I thought it was an emulsifier? Surely water in the fuel tank is already demulsified - as in separate and sitting under the fuel?

 

This ad claims Fuel Set has biocide properties, but I guess it could claim that the diesel bug is killed as a result of water removal.

 

https://marinestore.co.uk/fuel-set-fuel-conditioner-concentrate-1-litre-2002-j160224.html?

 

In fact diesel bug grows at the interface of diesel and water, so unless it's emulsifying the water it's not going to stop it growing without a biocide.

Edited April 16 by blackrose

[Tony Brooks]

1 minute ago, blackrose said:

 

I might be wrong but I thought it was an emulsifier? Surely water in the fuel tank is already demulsified - as in separate and sitting under the fuel?

 

You may be correct, but there were problems with "rafts" of bug forming at the water - fuel interface. As reported to me Eberspatcher amongst others. The point I was trying to make is that it was/is not a biocide, so comparing it with them is not really fair. Another in a similar vein was Fortron. It "killed" bug by a different process to the biocides and I think it needed longer to work.

[blackrose]

I edited my post above. Fuel Set claims to "kill" diesel bug.

 

You say it's not fair to compare it to other products that contain biocides, but that's exactly what the PBO tests did.

Edited April 16 by blackrose

[Momac]

1 hour ago, alias said:

Can't remember exactly when I bought it, but it was the last couple of years and the expiry on it is this September I think.

A search suggests it was 2022 when they started to add an expiry date. So no so recently as I imagined.

[wakey_wake]

3 hours ago, Jen-in-Wellies said:

I've not had any goldfish in my diesel tank either,

Exactly the analogy I needed - the watery version of elephant powder.

 

3 hours ago, pearley said:

As I have diesel stove I use a fair bit of Marine 16 so buy 1 litre bottles @ £51.95

Either it's gone up 50% since you bought, or we all want to know where you got that price!

 

3 hours ago, Tonka said:

Where did you find the shelf life info? Because I used to have a larger bottle and as only filling up twice a year it lasted ages

Only the thread I quoted. Yes I got a bigger bottle, longer ago and it probably has no mark on the bottom. I regard the stuff as so toxic I'm loathe to invert the bottle to find out.

 

Then I came to wonder "can it actually expire or go off or get used up?" because it's hardly going to go mouldy is it?!

I guess some component may oxidise. The way fats can go rancid, even while in the freezer. It's not a biological process, just one that can interfere with biology.

 

 

1 hour ago, blackrose said:

That's the problem, they ALL sound like they do the same job, but the reality is they don't. Remember Fuel Set? Turns out it was useless. 

 

The reason Marine 16 became popular is because it was independently tested alongside about 5 other brands about 20 years ago and the results published in Practical Boat Owner. The results were quite varied with Marine 16 along with Grotmar? coming out on top.

 

Right up there with magnetic limescale prevention. (I have no proof it doesn't work, but I wouldn't buy it without proof that it did)

and the best way to sell a lot of elephant powder is to get a reputable magazine to run a test to see which elephant powder repels the most elephants. (I may here be mixing my metaphors in an unhelpful way)

 

However the need for a biocide seems well demonstrated by those unlucky enough to grow the bug. All we actually need is a flammable poison that is also somewhat water-soluble... so I'm looking to the Wynn's version and wondering.

[Mac of Cygnet]

It doen't inspire confidence that the Wynn's stuff repeatedly states that it is active against algae.  There's hardly going to be any algae in a fuel tank, unless it is translucent. Only in the small print is this extended to include bacteria and fungi.

Also, regarding Marine 16's shelf life, I had a half bottle turn into a dirty brown sludge after a couple of years sitting under cover outside.

[wakey_wake]

I guess it's possible to get a jamjar of diesel, add some rainwater and a sample of bug, let it grow, and then attempt to shock-treat it with the Wynn's.

 

1 minute ago, Mac of Cygnet said:

It doen't inspire confidence that the Wynn's stuff repeatedly states that it is active against algae. 

Yes, I thought that was odd.

 

1 minute ago, Mac of Cygnet said:

Also, regarding Marine 16's shelf life, I had a half bottle turn into a dirty brown sludge after a couple of years sitting under cover outside.

🤯 sounds like bug growing in the DBT?

Mine looks OK, now 3½yo plus however long it sat on the shelf.

 

Keeping it in the dark seems sensible, and I have not always done. Not to stop algae using the sun, but to prevent UV exciting bonds to split. The PET bottle is transparent to UV unless they added something to block that.

[Momac]

15 minutes ago, Mac of Cygnet said:

 

Also, regarding Marine 16's shelf life, I had a half bottle turn into a dirty brown sludge after a couple of years sitting under cover outside.

 

 

It could be better to buy  fuel additive in smaller bottles so as to avoid keeping part bottles in storage for long periods.

 

 

 

[pearley]

12 hours ago, wakey_wake said:

 

Either it's gone up 50% since you bought, or we all want to know where you got that price.

Searched online for best price. F10 Marine in eBay although looking again a few minutes ago I should have bought two 500ml bottles which would have saved another fiver.

 

Manufacturing date states 14 November 2025 and expiry date 13 November 2028 so 3 year shelf life.

 

[MtB]

I have a small bottle (100ml probably) of Marine 16 sitting on the worktop in my galley should I ever need it. Been there five or six years at least. Its still crystal clear, for what that's worth....

 

 

[Batavia]

On 16/04/2026 at 21:16, wakey_wake said:

 

Right up there with magnetic limescale prevention. (I have no proof it doesn't work, but I wouldn't buy it without proof that it did)

and the best way to sell a lot of elephant powder is to get a reputable magazine to run a test to see which elephant powder repels the most elephants. (I may here be mixing my metaphors in an unhelpful way)

 

If I recall correctly, the testing was done by ECHA Microbiology, who are the Go To people for many major oil companies  when they have a serious fuel contamination issue - like a dodgy 80,000 tonne cargo.  Some credibility should be placed on their findings.   

[Tony Brooks]

18 minutes ago, Batavia said:

If I recall correctly, the testing was done by ECHA Microbiology, who are the Go To people for many major oil companies  when they have a serious fuel contamination issue - like a dodgy 80,000 tonne cargo.  Some credibility should be placed on their findings.   

 

Who, as I understand things, also supply materials, so arguably not as independent as one would hope. That is not to say their results were tainted by their own interests, but they might have been.

[Bee]

This is something that needs a bit of research for boat owners. I have had a diesel car for 10 years or so, no water ,sludge or bug whatsoever, I've also had a lifetime around HGV's with no problems at all and never a spot of additive. So why did I get a horrible fuel problem on my boat? I am not sure about the usual explanation of condensation or filler caps allowing rainwater in. Starting to think that draining the tank over winter might be a better idea than filling it right up or that mild steel might not be the best material for tanks because of the horrible sludge that the tiniest drop of water produces with the inevitable rust spots. Perhaps stainless steel might be a better material.

[wakey_wake]

3 hours ago, Batavia said:

If I recall correctly, the testing was done by ECHA Microbiology, who are the Go To people for many major oil companies  when they have a serious fuel contamination issue - like a dodgy 80,000 tonne cargo.  Some credibility should be placed on their findings.   

That is interesting, but with no feasible mechanism for the effect I'm in the "extraordinary claims require extraordinary proof" camp.

 

35 minutes ago, Bee said:

This is something that needs a bit of research for boat owners. I have had a diesel car for 10 years or so, no water ,sludge or

Car fuel tanks are sealed, presumably with a PRV. You know the hissing noise you get when you open the filler?

I think the aim was to avoid venting the volatile hydrocarbons, for environmental reasons?

It must also reduce the fire risk in a multistorey car park full of petrol cars?

I can't see it does much for diesel but my car seems to have it.

 

One of the devices sold by Marine16 is a desiccant container for the fuel tank. How on earth one is supposed to mount this is anyone's guess, and the eyewatering price for something that looks to be 3D-printed?

 

I would like to replace my 'spider trap' fuel breather with something ducted, through a desiccant trap well above the tank. There are practical issues and presumably also BSS issues. Anyone interested in that?