I was advised to use BioBor, so I do.

My only problem with massive fuel tank contamination from internally-generated gunk was my first passage in very rough water while motoring in 2004. I was on my way to the yard for other work and had them clean the tank. Since then I have used clean fuel and BioBor and have not had an issue.

I can't say that the BioBor is the reason for the lack of problems since then, but so far so good.

I use BioBor with every fill, and also some Startron water dispersant with each fill. I think it's a Good Idea.

I refill every 20 hours with ten gallons in our 23 gallon tank. No issues in 13+ years.

We use Stanadyne Performance Formula. From the reading I did it seemed to be widely accepted as being useful as opposed to snake oil. It is not an algae additive though.

Which brings up a thought, does anyone know if there are any ill effects from Ultra Low Sulfur diesel in older diesels? It's about all that's available up here now.

Speaking of fuel - on my last trip to Half Moon Bay I notices that the diesel that I purchased was not labeled as #2. It did indicate that it was high sulfur. Does it mean that I should not use in my engine. I had no choice since # 2 was not available. Does this cause a problem for the engine or is #2 low in sulfur and therefore low in pollution. For the last 18 months I have added about 200 hours on my engine and I have not used any additives. I have had no problems. Should I be using some additive?

I've been using ULSD diesel since I purchased "Sceptre" over two years ago and I'm sure the PO used ULSD also as that's what's been available in CA for many years now. I've had no problems with my fuel and I've put over 200 hours on the engine over the last two years (SoCal Noserlies), it's also been in seas getting knocked about fairly good and have no problem with sediment being disturbed in the bottom of the tank. The only thing I do religiously is keep the fuel tank topped up to full (even if it only requires five gallons) and I change the filters every 75 hours. I check the Racor water separator bowl before starting the engine every time. So far, all's well.

I have a 1994 C36 two cabin, with 25 gal tank. I use a product called "Sentry" which is made in Florida and may not be available everywhere. It was recommended by the tank cleaning guy as he also ran a test lab where he test these additives and told me that Sentry was the best performer when it came to water absorbtion. His position was that eleminating water or keeping it to an absolute minimum was the answer to all the fuel issues because the algae can't grow without water. He also recommends keeping the tank topped off all the time to eliminate the space for the water vapor to form. The additive is highly concentrated and only takes about a cup to a tank. Its now the only additive I use. I sailed across the Gulf of Mexico in 36 hours with stormy conditions and the engine never missed a beat.

Sam

I now use nothing but a biocide, perhaps once per year.... My fuel polishing system takes care of everything I need it too. I and the PO used Startron/Soltron religiously for perhaps 18 combined years and it did SQUAT!

These are the filters after 190 hours..

Polishing and on-engine filter @ 190 hours..
[IMG]http://www.pbase.com/mainecruising/image/131336758.jpg[/IMG]

Maine Sail has an article on his website about changing his fuel tank and his polishing system is described and pictured there:

[url]http://www.pbase.com/mainecruising/replacing_a_fuel_tank&page=2[/url]

His web site is a wealth of information, much of it directly related to C36's. You won't be wasting your time if you spend a while there.