Is this algae?

[Drift Woods]

The picture is of a Racor 15gph filter after approximately 110 hours. The clear bowl had 1/4 inch of the same material in it with no water. It's now been 6 months and 50 hour so I replaced the filter again. I found nothing on the filter this time but I'm still getting some on the bottom of the bowl. The engine is a 1996 3gm30f if that makes a difference.

I have no access panel on the tank and the sending unit is in a ridiculous place to get to for a look. It was recommended I use a mantnance dose of Valvtect BioGuard to stop any new growth. The thinking is that my problem is minimal now and with regular filter changes and BioGuard in each fill up it shouldn't get any worse. But of course he's not the one coming through the inlet bridge with the tide ripping.

Does this sound reasonable to you?

Thanks in advance, Woody

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[Lepke]

Looks like it. The best stuff I have used is Algae-x. I have mild steel 1942 built tanks that sat 6 years before I bought this boat. With Racor 30 micron filters and later 10 then 2 micron, my tanks are clean except for some surface rust that appears if I leave them empty. I also have a Algae-x inline magnet that catches any rust flakes, but is supposed to somehow make the fuel burn better. Found on many commercial boats.
My tanks are clean. I now run 2 micron primary filters all the time. I'm careful about where I buy the fuel. Docks serving commercial boats not yachts, etc.

[roverhi]

Use a biocide even in colder climates, frequently in warm ones. Bugs like diesel and will make filter clogging goo if left to their druthers. Wouldn't go with a 2 micron filter straight from the tank. You are asking for an unexpected engine shutdown should any gunk get picked. 10 or 20 micron filter will not clog as readily. Save the 2 micron filter for the final filter.

[Drift Woods]

Originally Posted by Lepke

Looks like it. The best stuff I have used is Algae-x. I have mild steel 1942 built tanks that sat 6 years before I bought this boat. With Racor 30 micron filters and later 10 then 2 micron, my tanks are clean except for some surface rust that appears if I leave them empty. I also have a Algae-x inline magnet that catches any rust flakes, but is supposed to somehow make the fuel burn better. Found on many commercial boats.
My tanks are clean. I now run 2 micron primary filters all the time. I'm careful about where I buy the fuel. Docks serving commercial boats not yachts, etc.

That's good news, every search I did on algae in tanks had gotten so bad they ended up removing them. I'm running a 10 micron Racor primary now with a standard Yanmar filter on the engine.

Thanks, Woody

[boatpoker]

it is absolutely impossible for "algae" to develop in a diesel fuel tank.
"Bacteria" can grow at the fuel/water interface if there is some water in your tank.