Photograph of a residential outdoor above ground oil tank - was this tank intended for outdoor use? Photo courtesy Arlene Puentes, Kingston NY Oil Tank Additives, Chemicals, Treatments
Types of oil storage tank additives used to reduce corrosion, disprese sludge, prevent waxing

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Oil tank additives, chemicals or treatments as water or sludge problem solvers or to retard oil tank corrosion:

this article describes the use of chemicals, additives or treatments for heating oil storage tanks to address problems with oil tank contamination by water or sludge, icing, waxing, heat loss, heating equipment damage, and to address oil tank leaks caused by internal oil tank corrosion caused by water & bacteria in the oil tank.

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Water or Sludge Removal & Anti-Waxing Additives for Indoor or Outdoor Oil Storage Tanks

Water problems in oil tanks

Below-grade oil tank filler invites water entry (C) Daniel FriedmanWhy might we use Heating or Fuel Oil Additives for Water, Sludge, & Waxing or Gelling Problems at Outdoor Oil Tanks?

As we discuss at ABOVE GROUND OUTDOOR OIL TANKS, water can get into oil storage tanks from a variety of pathways, leading to heating equipment damage & loss of heat.

[Click to enlarge any image]

In addition to causing short term heating equipment damage and loss of heat (with the building damage risks associated with heat loss) water in oil tanks or piping can freeze leading to a direct loss of oil supply to the heating equipment.

Our photo (left) shows a below-grade-level filler pipe opening for a buried oil storage tank - a design that invites water leakage into the tank through the filler cap.

You may also suspect from the color of liquid in this oil filler pipe cover that there has been oil spillage right at the filler itself.

Waxing Gelling problems in oil storage tanks

Oil tank exposed outdoors, heat tapes (C) Daniel FriedmanAt HEAT TAPES on OIL TANK PIPING we comment that when finding heat tapes on oil tank piping such as at this Hyde Park New York installation of an outdoor above ground tank we guess that the owners have had a problem with either water freezing in the oil lines or waxing and gelling in the oil piping system, either of which lead to loss of heat.

Waxing or gelling of heating oil in outdoor oil tanks is an additional problem in cold climates, heating or fuel oil additives for above-ground outdoor oil tanks can help prevent loss of heat by adding a pour point depressant which lowers the temperature at which the heating oil will form waxes or jell, and by adding a chemical, typically an alcohol, to remove [small amounts] of water from the oil.

I've used a product called 4-in-One Hot™ which contains both a sludge break-up chemical and alcohol to help remove water from the heating oil. Such additives may indeed help break up sludge which tends to clog old heating oil lines. But I'd cite two warnings about using heating oil additives and chemicals for outdoor oil tanks:

  1. No oil additive is going to remove a large quantity of water from an oil tank. Measure the amount of water present. If it's inches, your oil company can pump the water out (leaving the heating oil intact).

  2. Oil additives that break up sludge might in some circumstances precipitate frequent clogging of the oil filter installed at your heating boiler or furnace since an increased amount of debris is being freed and sent along the oil lines. If you find that your boiler stops working shortly after receiving an oil delivery, check to see if the problem was a clogged oil filter.

    That would suggest that your tank has a lot of debris and that the debris or sludge were being stirred up whenever oil was delivered. Discuss this concern with your heating service contractor.

Pour point depressants for heating oil tanks are about the same as similar products used by owners of diesel fuel powered automobiles and trucks in cold climates, but except in dire emergency I would not recommend substituting one for the other as there are some differences in these fuels and chemicals.

Note: these tips are not a complete oil tank installation guide. Proper installation must be done by trained service technicians and must comply with local building codes.

See HEATING OIL CLOUD WAX GEL POINT for details about heating oil waxing or jelling.

How to use an Additive to the Heating Oil Tank to Gradually Break Up Sludge or Remove Water

At HEATING OIL SLUDGE where we describe a variety of methods for dealing with sludge, crud, or water contamination in heating oil storage tanks, we introduced the use of additives intended to help remove water and sludge from the oil tank. Here we explain that approach in detail, including warnings about trouble that may arise.

How to Gradually Remove Oil Tank Sludge Without System Clogging

An example of a heating oil additive used by some oil companies to both prevent sludge build-up in modern heating oil tanks and also to (over time) remove sludge in an existing older heating oil tank is "Ultra Guard" a product from Beckett Additives.

One of our local heating oil delivery companies (Nash Oil, Dutchess County NY) informs us that they are the only local heating oil delivery company who uses this additive in their heating oil. The oil tank delivery truck drivers base their opinion on what they see. We're told that the interior of the Nash Heating Oil Truck Tanks is visibly clean as a result of using heating oil with a "maintenance dose" of Ultra Guard™.

Some heating oil technicians may recommend that a "treatment dose" of this additive be tried in an older oil tank which has been suffering from a sludge problem in the tank or oil lines. If this product works as claimed (there is evidence for it) you may be able to avoid an expensive oil tank replacement for an older oil tank which is sludge-contaminated but not leaking. Ask your heating oil company about this or similar products.

4 in 1 Hot Oil Tank Treatment (C) Daniel FriedmanNote that this product is not a pour point depressant to avoid waxing or gelling, but sludge, too, can lead to a loss of heat which may be exacerbated in cold weather. (More frequent deliveries, running the oil tank too low on oil, stirring up sludge during oil delivery, clogging the oil burner filter or nozzle as sludge passes through the system all can lead to loss of heat in a building.

Shown at left" 4-in-1 Hot home heating oil storage tank treatment. The manufacturer has since updated the product label and appearance.

What Happens when we use an oil tank additive to break up sludge?

When we added a pour point depressant to our heating oil we hoped it would also break up the sludge - after all, the product also claimed to break up sludge - which sounds good if the oil lines are old and perhaps partly blocked with sludge.

But in this case the combination of use of a heating oil additive with a "de-sludger" combined with the sludge agitation up from the bottom of the oil tank during filling of a nearly empty oil tank led to loss of heat from filter clogging.

Problems With Heating System Reliability When Heating Oil Additives are Used or Low-Level Oil Tanks are Filled

Watch out: anything that significantly disturbs accumulated sludge in a heating oil storage tank risks sending that sludge-crud through the oil piping to the oil filter and oil burner assembly where clogging can lead to loss of heat and even recurrent loss of heat difficulties. One way that oil tank sludge gets disturbed is when an "empty" or nearly-empty oil storage tank receives an oil delivery. The pouring of heating oil against the oil tank bottom disturbs accumulated sludge there.

When we serviced and installed heating equipment we often recommended use of heating oil additives to remove small amounts of water or sludge in oil storage tanks, or to act as a pour point depressant for outdoor aboveground oil storage tanks. But while these are good products, things didn't always go well.

If additives to a heating oil storage tank send increased levels of broken-up sludge through the oil piping too rapidly the risk is that we are sending that crud right into the oil piping, valves, filter, screen, fuel unit and oil burner nozzle: asking for clogs at any point along the way.

Watch out: also it's worth noting that while water entry prevention or removal is probably the most important step in preventing oil storage tank corrosion, Bento et als (1991) pointed out that oil tank additives themselves may play a role in biodeterioration agent formation in oil tanks "... sub-effective doses may lead to increased microbial growth" and Hendey et als (1964) note that steel is not the only storage tank metal of concern, finding that aluminum storage tanks could be attacked by fungi. Also see OIL TANK LEAK or FAILURE MECHANISMS.

Oil Storage Tank Corrosion Inhibition: reducing the rust & corrosion risk on & in oil tanks

Reader comment: Benefits of using Tank-Guard® corrosion inhibitor in oil storage tanks

Robert Messia Apr 29 2014

I work for Lincoln laboratory in Leicester MA. We manufacture a corrosion inhibitor called tank guard. When this additive is poured into an oil tank it goes to the bottom to stop the ongoing rust and pitting of the oil tank. This will help prolong the life of the tank. We sell the tank guard program to the oil dealers so they can offer it to their customers. Depends on the companies location we can offer a free oil tank or a $ 1000 reimbursement.

I recently read your article on the ultra-sonic tester [OIL TANK LEAK TEST METHODS]. There is a company out of New Hampshire who sells that testing program to the dealers. We have had some oil dealers switch to our program because they did not believe that you could properly test a tank. We have performed testing at our office and found out that the tester could not even find a pin hole that was on a leaking tank.

Our warranty program is the best in the industry as we are treating the customers tanks as a proactive measure. If you have any questions about our program feel free to contact me. You can also check us out on our website.

Regards, Bob Messia


I much appreciate your very interesting note. ... Without slipping over into promoting individual products or services (to preserve reader credibility) I'm still happy to cite & refer to appropriate products, test approaches, &c. I'll paste in some details below.

The tank testing I observed was combined with a visual inspection, without which it would be absurd as I agree that spot testing over 9 or even 12 points to measure metal thickness does not promise to find every possible leak point. That program also includes a tank warranty.

More detail about the chances that an oil tank is leaking or about to leak is at TANK FAILURE RATES.

I suppose if the method were very badly flawed the vendor of the tank insurance (via the oil company) would take a terrible beating and would quit the program. In the insurance industry it's called adverse selection - only the people who are likely to have a claim sign up for the program. (Adverse selection killed the used-home warranty program offered by some companies as a real estate marketing tool a while back.) - Daniel Friedman

Oil Tank Treatment & Additive Products

Oil Tank Corrosion Protection References


Continue reading at OIL TANK WATER REMOVAL or select a topic from the More Reading links or topic ARTICLE INDEX shown below.

Or see ABOVE GROUND OUTDOOR OIL TANKS how water gets into oil tanks and we describe the problems caused by water.

Or see HEATING OIL SLUDGE methods for dealing with sludge, crud, or water contamination in heating oil storage tanks. There we introduced the use of oil tank additives intended to help remove water and sludge from the oil tank. Here we explain that approach in detail, including warnings about trouble that may arise.

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OIL TANK TREATMENTS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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