Biocide

Curious thoughts on biocide. Currently I only use howes diesel treat to add lubricity. I am starting to see a buildup of bio algae in the water separater. About 1/2 inch build up over 400hrs and 2400litres of fuel.

Is this normal or should I start adding an additional biocide?

TIA!

Randomwake said:

Curious thoughts on biocide. Currently I only use howes diesel treat to add lubricity. I am starting to see a buildup of bio algae in the water separater. About 1/2 inch build up over 400hrs and 2400litres of fuel.

Is this normal or should I start adding an additional biocide?

TIA!

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I wouldn't want to see any buildup after you empty what's there.
Find the source of the water contamination. Growth requires water.
No water in your fuel equals no 'bugs'. I would use BioBor to kill 'em.

Biocide will kill whats alive but you still need to run what fuel remains to filter them out. After cleaning a biocide is effective at preventing future growth. As mentioned eliminating any / all water is key for ongoing health & prevention.

Spend some quality time with these two articles from Steve D'Antonio. Steve is a classic case of forgetting more than I'd ever know....

https://stevedmarineconsulting.com/diesel-fuel-additives-part-i/
https://stevedmarineconsulting.com/diesel-fuel-additives-part-ii/

Peter

Better additives include biocides, boosts cetane, improves combustion efficiency that increases fuel economy, lubricates, and cleans injectors.
What I use gives me all of that and 10% better mileage. It costs about 9¢/gallon to treat.
https://www.archoil.com/collections/products/products/ar6500-diesel-treatment

Every fall upon my arrival back to the Columbia River I prepare for winter by shocking my fuel tanks with brocade and lubricant. This keeps the tanks fresh and free from most contaminates. By spring I do have dead critters in my Racor.

I use one bottle per 250 gallon tank (2 each) and half bottle in each 50 gallon tank (2 each). On the Lucas 1gallon bottles.

https://www.westmarine.com/biobor-b...e-and-lubricity-additive-32-oz.-10932747.html

https://lucasoil.com/products/fuel-treatments/lucas-fuel-treatment

Lepke said:

Better additives include biocides, boosts cetane, improves combustion efficiency that increases fuel economy, lubricates, and cleans injectors.
What I use gives me all of that and 10% better mileage. It costs about 9¢/gallon to treat.
https://www.archoil.com/collections/products/products/ar6500-diesel-treatment

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If the link you posted is what you're using then it contains no biocide.
That's a good thing.
True biocides are fairly aggressive chemicals which are not needed as long
as the fuel is 'dry' and uninfected.
As a rule I focus on keeping water out of diesel and avoid using biocides.
Think of biocide use the same way we should use antibiotics, i.e. to treat an
active infection.

KnotYet said:

If the link you posted is what you're using then it contains no biocide.
That's a good thing.
True biocides are fairly aggressive chemicals which are not needed as long
as the fuel is 'dry' and uninfected.
As a rule I focus on keeping water out of diesel and avoid using biocides.
Think of biocide use the same way we should use antibiotics, i.e. to treat an
active infection.

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A quick way to see if your tank is contaminated is to look on the underside of the fill cap. Water droplets? Tank is contaminated.

With all due respect, I disagree with the statement on biocide.

Kill the bugs, yes.
But also get rid of the water or you will not actually get rid of the bugs , long term.
Also figure out how the water is getting into the tank.

It can enter of course from a questionable fuel supplier although that is FAR less likely these days than it used to be although it can still happen.

There are several other sources though:
--fuel filler caps. Should all have O rings of the right size, in good shape and greased lightly for a more effective seal and to protect the ring from being damaged. The actual metal sealing areas should be clean of any debris so the O ring can make contact all the way around its diameter. New O rings should be installed every 3-4 yrs. I change mine about every 3-4 yrs and grease them yearly at a minimum.

--poorly sealed fuel deck fittings and then a loose hose not tightly secured to the hose bib by a loose clamp. All hoses take a set over time, shrink, which releases the pressure from the clamp and may allow any water that sneaks between the fuel fitting and the deck from a poorly sealed installation to enter the tank. THe deck to fitting must be sealed properly.

--The tank vent can be a source if not done properly. THe vent hose should go up higher than the actual vent and then use a couple of 90o fittings to aim the final connection down to the hull vent.

--Second, the actual hull vent must be angled backwards , about 45o, so spray and rain cannot enter even in rough water and weather.

Between the down join of the vent hose and the backward angles of the fitting no water should be able to enter via the tank vent hose.

-

Good post

This is worth reading.

KnotYet said:

If the link you posted is what you're using then it contains no biocide.
That's a good thing.
True biocides are fairly aggressive chemicals which are not needed as long
as the fuel is 'dry' and uninfected.
As a rule I focus on keeping water out of diesel and avoid using biocides.
Think of biocide use the same way we should use antibiotics, i.e. to treat an
active infection.

Click to expand...

Sent an email questioning biocide, this is Archoil's reply:
AR6500 detergent package will deter growth with dispersing water and dissolving sludge/ organic matter.

I've been using their products for about 11 years. In that time, no bio growth issues, I run 2 micron filters, and no injector replacements.

Lepke said:

Sent an email questioning biocide, this is Archoil's reply:
AR6500 detergent package will deter growth with dispersing water and dissolving sludge/ organic matter.

I've been using their products for about 11 years. In that time, no bio growth issues, I run 2 micron filters, and no injector replacements.

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Your experience reinforces the point that routine use of a biocide is unnecessary.
Keeping the water out of your tanks will keep the growth out, too.

Randomwake: What material is your fuel tank made of? If this is just starting, as you stated, it could be a condensation problem if your tank(s) are metal and not filled all the way up. As it is getting colder, the problem will get worse with the temperature differences. Until I owned a steel boat, I didn't appreciate the amount of condensation that accumulates on a metal surface that is cold on one side and warm on the other. I like Biobar along with keeping your tank full in the colder months. I wonder if the price of fuel will make this more of a common occurrence.

First step is to use this test kit. https://skygeek.com/fuelstat-hr-2-011-aviation-jet-fuel-test-kit.html?utm_source=googlebase&utm_medium=shoppingengine&utm_content=fuelstat-hr-2-011-aviation-jet-fuel-test-kit&utm_campaign=froogle&gclid=Cj0KCQiA4aacBhCUARIsAI55maHGpSZMFf2JHRPe94GohD4x5-1s2ZOOUjYmgkd8tqc01B8YSPUaWFYaAkVLEALw_wcB

The Fuelstat kit is actually a recent invention that has saved aircraft owners and operators millions of dollars. Its an accurate test that gives rapid results. And if it comes up positive it gives a range of the severity of contamination and guidance as to how to treat using Biobor JF. You can look at gunk in your racor and assume its bugs but it may not be. Or it may have been from the past. Or it may be active and raging. The Fuelstat kit will tell you that. I contacted them directly 5-8 years ago when it first hit the market. We had to get approval to use this as a valid test from engineering. We were basing tens of thousands of dollars of maintenance on visual evidence alone and there were often disagreements amongst technicians, QC and owner/operators (bill payers) whether or not something was microbial contamination. The old Humbug test kit was massively unreliable. When we switched to the Fuelstat it was like having a DNA test as evidence. This silenced all disagreements. We also found that many instances that were assumed to be microbial contamination was not. If it was positive the result would tell us whether we needed to do a shock treatment or just begin using a Mx dose of Biobor JF.

Whoever said Biobor was an aggressive chemical is correct when its used as shock treatment. On aircraft its very expensive. You have to top off the tanks using the large doses stated on the biobor label for shock treatment. Transfer fuel in various ways to get the biocide through each and every pipe. Bleed it right up to the engine and then let it sit for something like 24 or 48 hours (cant remember). Then you have to DISPOSE of the fuel . Thousands of gallons. Change all filters etc.

If you do a Mx dose you can burn the fuel during normal operation.

Obviously we are not operating aircraft, but these stringent rules can inform you in crafting an approach if you believe you have microbial contamination. If its confirmed through testing to be severe there are certainly additional steps to take after shock treatment that may not need be done if its minor.

But I believe you should start with a good test.

You need to do two things for clean fuel. Kill the bugs, then get the dead bodies out of your tank.

Sounds like you are halfway there. Time for a fuel polishing.

pete

KnotYet said:

If the link you posted is what you're using then it contains no biocide.
That's a good thing.
True biocides are fairly aggressive chemicals which are not needed as long
as the fuel is 'dry' and uninfected.
As a rule I focus on keeping water out of diesel and avoid using biocides.
Think of biocide use the same way we should use antibiotics, i.e. to treat an
active infection.

Click to expand...

I totally agree. Using a biocide is treating the symptoms of another problem. Fix the problem, meaning keep water and contamination out of your fuel, and you won’t need biocides. The stuff is nasty and better avoided unless really necessary.

wow a few anti biocide. Wonder what the bottom of their tanks look like? The stuff I use (see post #6) gets rid of water and other contaminates.

I would agree that if you have a bunch of crap on the bottom of your tanks biocide by its self will not work. You will need to clean your tanks, then follow-up with periodic maintenance.

When we bought ASD I paid to have the tanks clean and have access hatches installed. He was the one that told me how to treat the tanks using items in post #6. He stated that I paid a lot of money to clean the tanks, periodic maintenance was the key to keeping the tanks clean and free of contamination. Paid around 6 boat dollars for the work. Worth every $100.....

fgarriso said:

This is worth reading.

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Absolutely. Great articles.

Random
Do your filters show lots sludge? Also, what kind of water separator do you have?

Alaskan Sea-Duction said:

wow a few anti biocide. Wonder what the bottom of their tanks look like? The stuff I use (see post #6) gets rid of water and other contaminates.

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We’ve burned way over 20,000 gallons of diesel in this boat and our Racors stay clean on even a bumpy offshore passage, so I think we are doing pretty well so far. Our fuel pickups are from sumps at the lowest point of the tanks, which should help most stray contaminants flow through to the filters.

I’m not anti-biocide, I just think it is better avoided unless you have a problem to treat. It is pretty toxic stuff and has no benefit if your fuel is clean and dry.

The risk of moisture and growth is often higher in warm and humid weather. We have had no fuel issues at all in the PNW, BC and Alaska. Hold on a second while I go knock on some wood.

guy with a boat said:

We’ve burned way over 20,000 gallons of diesel in this boat and our Racors stay clean on even a bumpy offshore passage, so I think we are doing pretty well so far. Our fuel pickups are from sumps at the lowest point of the tanks, which should help most stray contaminants flow through to the filters.



I’m not anti-biocide, I just think it is better avoided unless you have a problem to treat. It is pretty toxic stuff and has no benefit if your fuel is clean and dry.



The risk of moisture and growth is often higher in warm and humid weather. We have had no fuel issues at all in the PNW, BC and Alaska. Hold on a second while I go knock on some wood.

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Good post. If you have water on the inside of the fuel cap, you are contaminated. Agree more a problem in warm weather, but Temps in the PNW were in the 90s this past summer.

Better to eliminate the issue BEFORE it becomes a problem. Instead of changing filters in the middle of 6ft seas.

Alaskan Sea-Duction said:

Good post. If you have water on the inside of the fuel cap, you are contaminated. .

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Even under the best practices there is water in freshly delivered diesel, somewhere between 0.05 and 0.1%. In large tank farms tens of gallons of water per day are collected in the various types of moisture traps.

As tanks warm and cooldown air is pulled in through the vents with moisture then coalescing on tank innards, including the fill cap.

Excess moisture entering through leaky fill caps, holes in tank tops or water entering through the fuel vents is normally the water that cruds up tanks and filters as stuff grows.

The easy test, if you have vertical fills, is to use a dip tube to draw fuel from the bottom of your fuel tanks and check for clarity.. Or if you have a bottom tank valve collect some fuel in a mason jar.

sunchaser said:

Even under the best practices there is water in freshly delivered diesel, somewhere between 0.05 and 0.1%. In large tank farms tens of gallons of water per day are collected in the various types of moisture traps.



As tanks warm and cooldown air is pulled in through the vents with moisture then coalescing on tank innards, including the fill cap.



Excess moisture entering through leaky fill caps, holes in tank tops or water entering through the fuel vents is normally the water that cruds up tanks and filters as stuff grows.



The easy test, if you have vertical fills, is to use a dip tube to draw fuel from the bottom of your fuel tanks and check for clarity.. Or if you have a bottom tank valve collect some fuel in a mason jar.

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Back in the early days when I worked at a gas station, every night I had to "dip" the tanks. There was this putty stuff you put on the end of the dip stick. If water was present, it turned pink.

Other thing to prevent troubles is to use your boat. If you’re using the boat in effect you’re getting some polishing. Also if your using your boat most tanks draw from low enough even if you don’t see rough seas you are creating some currents through the bottom of your tank(s) even with the baffles and this will make your racors do their job. Also the more fuel going in and out the less time for colonies to get well established. Think boats that aren’t used much are at the greatest risk for troubles.
We try to only use Valvtect. If boat is stored try to leave tanks full and a maintenance dose of biobor in them. That’s gone after the first tank. When I got the current boat the main engine ran fine (draw from port) but the genset would die (water and crud) It drew from starboard. There’s a crossover but even so only one tank was dirty. Since have cleaned it and all is good. Boat was only very lightly used for the prior 5 years.

Valvetec diesel sold at many US marinas has a biocide premixed along with a bunch of other additives. Do the anti-biocide folks avoid Valvetec fuel?

Three years ago I had my tanks emptied and cleaned. The yard cut an access hole in the top of each 300 gallon saddle tank, removed the tank baffels and had a small worker go inside and muck out the tank. Each tank had 5 gallons of bio goo in the bottom. This accumulated after 40 years of service. I be sure to fill the tanks each summer before l lay up on the hard in Mexico so there is no opportunity for water condensation.

CarlF said:

Valvetec diesel sold at many US marinas has a biocide premixed along with a bunch of other additives. Do the anti-biocide folks avoid Valvetec fuel?

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I haven't read any anti-biocide posts, including my own. Only anti- routine use,
at least in my case. Valvtect fuels generally enjoy a good reputation and I would
not hesitate to use them, all the more reason not to have any unneeded biocide
already present in my tank(s).

Randomwake said:

Curious thoughts on biocide. Currently I only use howes diesel treat to add lubricity. I am starting to see a buildup of bio algae in the water separater. About 1/2 inch build up over 400hrs and 2400litres of fuel.

Is this normal or should I start adding an additional biocide?

TIA!

Click to expand...

No water, No bugs.
Bugs live in free water and eat the fuel.
We use jet fuel de-icer. Not alcohol. The deicer ties up the moisture and carry it out to be ‘burned’ with the fuel.

As others have said, eliminate the water and you have no need of a biocide, or water removal agent.

Few diesel tanks have a drain low enough to be used to drain all water, unless the tanks have a well and a drain in the bottom (rather than the side) of the well. In that case, you can add a stripper tube, details here https://stevedmarineconsulting.com/cleaning-diesel-tanks/

The well arrangement is shown in this article https://stevedmarineconsulting.com/wp-content/uploads/2022/11/FuelTanksPt1-193-FINAL.pdf

https://stevedmarineconsulting.com/wp-content/uploads/2022/11/FuelTanks194Pt2-06.pdf