Scum? Slime? Snot? Mold? In Heating Oil

Old 10-29-08, 09:34 AM
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Scum? Slime? Snot? Mold? In Heating Oil

I live in an older house (1958) with a Lennox oil heat (#2 oil) system with an underground tank (2 line system/return).
Near the end of last year, the tank was getting low (about 12 inches of oil as measured with a stick) and the filter and nozzle became clogged with what looked like the normal black chunky stuff from the bottom of the tank AND some whitish/yellowish snotty slimey looking scum.
I replaced the filter I had 100 gallons delivered, ran the system, then changed the filter again. When I changed the filter, it was clogged with more of this white slimey stuff. After the filter change, everything was working ok, then it warmed up and I was done using heat for the year.

Fast forward to this year....after about 2 weeks of off and on use, the heater cut off last night.
I checked the oil level in the tank and its at about 19 inches. I took out the filter and again, clogged with some whitish slimey snotty stuff.
I poured the contents (oil) of the filter housing into a mason jar and saw that the scum sinks to the bottom of the jar.
I did some reading on-line and it appears that mold or other bio-nasties commonly thrive in oil and oil tanks.
I have a friend in the HVAC industry and I'm waiting for him to call me back, but figured I would give the forum a try.
What can I do to get this slime out of the system?
Is there an additive I can use?
Should I have the tank evacuated/cleaned?
Should I replace the tank? Perhaps an indoor tank? (I have a basement)
Should I just get a couple hundred gallons of oil delivered and hope that it dilutes the slime or makes it so the slime remains below the intake?
Any and all suggestions appreciated !

Old 10-29-08, 08:43 PM
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Since this stuff sinks to the bottom in a jar of oil, I have to believe it is largely water. If there is a straight drop into the tank either from the fill or vent pipe, you might be able to use a hand or small electric pump to get some (maybe even most) of the water out.

Get rid of that 50 year old tank ASAP & install a tank in the basement. In the mean time, get a Tiger Loop, install it, & abandon the return line. That oil being returned to the tank is keeping the tank stirred up.

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