My tank had it around an inch thick- I tried the Startron tank cleaner, but it didn't really make a huge difference, so I had it cleaned by a radiator shop. The stuff dissolved with the Startron, but it was so thick that it clogged filters like there was no tomorrow. Now I'm using a dose of the fungus killer with each fill-up so as not to repeat this mess. It cost $45 (the two jugs of Startron, 20 inline fuel filters, and 3 spin-on fuel filters I went through cost much more).

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Andrew

1989 Volvo 745- 202K