Diesel Fuel Additive

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

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

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.

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.

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 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 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.