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Old 09-08-2019, 11:01 AM
DickWells's Avatar
DickWells DickWells is offline
Join Date: Jun 2000
Location: Morrisville, VT, USA
Posts: 2,353
Default Need advice on handling my algae fuel situation.

Getting near to head-for-Texas time, and I have ~40 gal of diesel in my 80 gal tank, that's been sitting there all Summer. You might have seen my notes on the algae fiasco that we experienced on our way back to Vt., last Spring.

The last 300 miles was without incident and the fuel that's in there has been heavily treated with algae killer, as was every tankful over the last 900 miles.
I went through 3 stock fuel filters over the last ~1200 miles.

Our son is convinced that I should drop that tank and do a thorough cleaning with ??? acid, and not take any chances. Well, I just crawled under there and did an assessment and it was enough to convince me that I'd rather spend a couple-hundred on fuel filters, than go through all the pain of wrestling with that tank. It's 7 feet long, almost 3 feet wide, and like, 1.5 feet deep; it's steel and must weigh 200 lbs. Lots of stuff to remove to access it, too.

What are your opinions? I'm hoping that experiences among the DP members will make me more comfortable about moving on with just the chemicals and filtration. BTW, I'm in the process of installing an Air Dog system in there.

Any and all advice will be well appreciated.
2008 Jaco Seneca 35' motor home (Kodiak 5500 chassis). Pulling 18' Wells Cargo enclosed trailer, with 2016 Miata in it.
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Old 09-08-2019, 12:09 PM
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DmaxMaverick DmaxMaverick is offline
Join Date: Apr 2001
Location: CA
Posts: 12,329

If you're content with changing filters, I don't think it will hurt anything. However, I suggest installing a clod sifter (10-20 micron) filter between the tank and OEM filter. You can get them that use inexpensive, common off-the-shelf cans. Racor and Baldwin come to mind. Greg Landuyt ( use to sell a simple setup that will adapt to just about any system or location, and it used common Baldwin spin-ons. He's a TDP supporter. Maybe contact him for info on that, or something comparable if he no longer carries it. Doing so will very likely minimize the cost of both filters over time, and certainly cover the cost of the new filter assy in the short run.

I also suggest adding a fuel system restriction gage ( to your toolbox inventory. It too, will pay for itself over time, by not replacing filters prematurely (eliminates the guesswork). I have one, and it earned its keep in less than 5 years with moderate miles and loads. Higher miles and/or loads may see a much sooner return.

Continued biocide treatment isn't necessary, as once they're dead, they stay dead, and don't contribute to new growth. Occasional treatment may be preventative, but no more for you than anyone else.

That said, if you've had a serious biological attack, you will have a significant amount of solids/particulates (dead critters) in the tank that may take a lifetime to filter out. Dropping/cleaning the tank is almost always necessary, ultimately, to continue normally. The trade off for convenience is up to you, but it's not something that will just go away, at least in a reasonable time or miles.
1985 Blazer 6.2
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Old 09-08-2019, 01:40 PM
rapidoxidationman rapidoxidationman is offline
Join Date: Dec 2002
Location: Teton Valley, Idaho
Posts: 1,779
Default siphon off a sample from the tank

Try to get the siphon tube all the way to the bottom of the tank, and then let it settle into the corner of a jug. See what's in there. If it settles out a bunch of goo, there's your answer.

I'd likely just run it, especially given that you've treated it already.
'85 Mercedes Benz 300D, for when I want to be stately.
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There's no point being a pessimist - it wouldn't work anyway.
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Old 09-09-2019, 06:13 PM
DickWells's Avatar
DickWells DickWells is offline
Join Date: Jun 2000
Location: Morrisville, VT, USA
Posts: 2,353

Thanks, guys. I forgot to mention that there's a drain in the tank bottom. Gotta think hard about putting a coarse filter in beteen the tank and the new Air Dog lift pump. Guess the deciding factor is what I see when I asses the curremt fuel condition. Plus, I'll pull the stock filter bottom water drain thingy and check for those coffee-grounds-sized particals that were in there with the first couple of filters that clogged on the way home in March.
Thanks for responding. With a little (maybe a lot) of luck I can dodge a bullet.
2008 Jaco Seneca 35' motor home (Kodiak 5500 chassis). Pulling 18' Wells Cargo enclosed trailer, with 2016 Miata in it.
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