Diesel Fuel Additive

Here’s a link to a recent gentile discussion on the topic:

https://www.yachtforums.com/threads/35-cabo-flybridge.32883/

I have not found the need for any “algae” treatment been in the south for 10 years now. I fill up my tanks every time I am going to leave the boat for any length of time. I thought I read that it was not algae but asphaltenes that people refer to as algae. Sorry I can’t get you any further.

Run the Mamma Jama! Boomer! Use the boat , that always helps. I used Biobor in my old tanks and that caused me snot ball problems.
Eventually just good old use of the boat got things back in shape.
Make sure you install new O-rings on your deck fills! Even if they ''look good'' , I would be sure they are new. They can leak easily. Any water in the tank gets things growing in short order.

Finally found some old pictures.
Here is what adding snake oil to my aft diesel tank did.
That is the screened end of the mains fuel pick up tube.

I use Archoil AR6200 every fueling. It keeps my tanks and fuel system free of organisms and helps the Racors separate out water. I run 2 micron primary filters and running clean fuel reduces wear on fuel parts. I haven't changed an injector on my Detroits in 10 years, about 500-600 hours a year. Ar6200 also helps fuel combustion. I get about 6% better mileage using it than with straight diesel. I started using it in my diesel truck. It made a huge difference, so I tried it in the boat. Available online at Archoil.com and usually on Amazon or eBay.

Thank you. And yet folks still endorse their fav snake oils.
Oh, this pic was after a big name brand snake oil.
So, repeat after me, Don't fix any thing till there is an issue. I further promise to use fresh fuel and cruise very often. Purchasing fuel from good vendors and checking filters often.
I further promise to send to Capt Ralph 5% of my fresh catch because he is such a nice guy.

Along with keeping your tanks topped off. But these are just outlines for the best case scenario.

What do you do if you cruise or use the boat only 3 - 6 months/times a year, your local fuel dock looks to cut costs and uses questionable suppliers, your cruising destination fuel dock is junk and you don’t come back to the boat for 6 months?

Sell shares in the boat so it gets used more or use the best boat in the world...you're friend's. Also you hear a lot of boaters have the truck pull up to their dock and save a few bucks. Cheap becomes expensive. It pays to get your fuel from places that pump a lot of fuel and have a quality product. Despite Capt. Ralph's experience I still believe in Bibor. It's been around for a long time. The fact is that algae grows in diesel tanks that sit idle. Even a topped off tank is 10% empty or should be for safety. That gives algae all they need to grow.

I ve never used anything in my boat or the boats i run. In my old 53 during the repower I had a local polisher remove old fuel (boat had sat for 5 years before repower ) and clean the tanks. That worked out fine for the forward tank but the aft tank still has some trash because of th angle the boat sat at in the Yard when the tanks were cleaned. Since we don’t have time to use the boat a lot, I m just running on the forward tank right now.

the key is to avoid water coming in which is why I never understand why so many fillers are on deck relying on a O-ring. During the repower I moved the fillers and vents to a box on the house wall about 18” above deck. No worries about water getting in... and I can easily catch spills during fueling. Should be this way on every boat

Yep, Great idea. I did this on my 34 Pequod (gas) and it worked great. Lil Racor whistle added to the vent at the same time.
Sadly, mods like this to our Bert are not available.

If you remember our aft tank water problems, it was not the O ring, the hose clamps under the deck failed (out of sight) and allowed the fill hose to expand just a lil. It would take fuel on fine because of good hose support below it (in sight). However, the fitting seal to the deck had long failed (40 years old caulk not considered). Water would run down the deck, under the deck fill, down the hose barb, into the loose old hose & into the tank.
To further cover up and keep this issue invisible, the deck fill was in the stb hull air box. Any water or a drop of fuel would drain overboard. Never witnessed or thought of.
F M

Amazing after I learned my lesson the hard way on my own boat, I have found it again on many other customer boats.

I may be mistaken, it's been a long time since biology class, but algae needs sunlight to grow. I've yet to see marine tanks that allow sunlight into them. More often, it's microbes that live in water and feed on the wax content of the fuel. Their carcasses and waste product (microbial poop) clog filters.
Power Service products puts science to work on analyzing fuels. I've run several boats for the owner over the last 18 years. He would have me take test tube samples of the fuel and overnight them to the lab for analysis. Basically, Ultra Low Sulpher Diesel ULSD is everywhere, even when the offroad marine fuel says it's Low Sulphur. The removal of sulphur allows microbes to thrive and water to precipitate to the bottom of the tank. Think of ULSD as if it has a 'shelf life'. It does not keep well for long periods of time like fuel did 20 years ago.

https://powerservice.com/boating/

Your Biology class served you well Kapn. Trouble is that most people are stuck on the word Algae when the real problem is microbes like mold, bacteria, and fungus which have everything they need inside the fuel tank, especially water and darkness. Biocides are used to kill these so they don't reproduce. The problem is then the carcasses. Only way to get rid of them is in your Racors or cleaning the tank when the problem becomes severe. IOWS once you have the problem it'll only get worse. The idea with biocides is to kill off the microbes as soon as they enter your fuel system so they don't multiply and hope most make it out to your Racors. That's why poor quality fuel along with lack of use are the perfect breeding ground. It's also one of the reasons boats with low hours aren't such a good deal. It's also why biocides help. You may have say 50 microbes enter your tank with the fuel, but that can become 5,000 in short order unless they're killed.

I wonder if you guys think I am nuts talking about asphaltenes and I am somewhat ashamed to admit I don’t know how to attach a website. But google asphaltenes in diesel fuel and you will see what I am referring to. It could be that people who are fighting black stuff clogging their filters are thinking algae is the problem when in fact it is asphaltenes which I believe requires a different treatment. I am far from a chemical engineer so I will not attempt to describe the situation. So if interested google it and see for yourself.

I just read up on this and must admit I'm a little perplexed. They say it's caused by the heat and high pressure of modern injection systems. I can see how that might clog injectors, but how does it get back to your fuel system? Next stop is the exhaust. Yes I know a certain amount of fuel is returned but it sounds to me like a cure in search of a problem.

It very may well be a cure in search of a problem. I sometimes think of the algae in that way. But yet there is black stuff that will find it’s way into some peoples fuel tanks. I don’t have the answers but thought I would let others know that asphaltenes MAY be there problem.