Water
Free water from condensation and ingress, plus emulsified water held in the fuel. Water is what lets diesel bug take hold and what corrodes injectors.
Service & maintenance · Commercial fuel tanks
Fuel polishing service for diesel tanks & generators
Stored diesel degrades. Fuel polishing circulates it through multi stage filtration to remove water, particulates and microbial growth, returning it to a clean, usable spec without draining the tank or buying new fuel.
- On site mobile polishing rigs, so the fuel stays in the tank
- Before and after fuel samples, so you can see the result
- Standby generator, day tank and bulk storage tanks
- One off clean ups or a scheduled polishing contract
15+ years in fuel storageUK & Ireland coverageDiesel · Gas oil · HVO
Get a fuel polishing quote
A few details and the service team will call you back with a price and the earliest visit date.
Usually answered within one working day. No obligation.
Contamination
What fuel polishing removes
Diesel doesn't go off in a day, but after a year or two in a tank it carries three things an engine can't tolerate.
Particulates and sludge
Rust, dirt and the dark sludge that forms as fuel oxidises. It blocks filters first and wears pumps and injectors after that.
Microbial growth
Live and dead biomass from diesel bug. Polishing strips it out and a biocide dose afterwards stops it regrowing. About diesel bug
The visit
How a polishing visit works
Our engineer connects a mobile polishing unit to the tank and circulates the full contents through staged filtration and water separation until the fuel comes back clean. The tank stays in service for most of the visit and nothing is wasted except the contaminants we take away.
We take a sample before we start and another when we finish, so you have a record for your maintenance file, and for an insurer or auditor if they ask.
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01
Survey and sample
Check access, bund and pipework, then draw a bottom sample to grade the contamination.
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02
Draw off free water
Water and heavy sludge come out of the tank bottom first so they don't load the filters.
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03
Circulate and filter
Fuel passes through coarse and fine filtration and a water separator, repeatedly, until it runs clear and bright.
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04
Treat, retest, report
Biocide or stabiliser dosed if needed, a final sample taken and a short report left with you.
Generator fuel polishing
Standby power is only standby if the fuel is good
A generator tank can sit for years between real outages. The fuel in it is the single most common reason a set fails on load. Data centres, hospitals, telecoms sites and water utilities put polishing on a fixed schedule rather than finding out during a power cut.
We polish day tanks and bulk tanks, work around your test windows, and give you dated samples for your resilience records.
Scheduled
Annual or six monthly polishing contract, with reminders handled by us.
Reactive
Failed test run or blocked filters, with a fast callout to get the set back on standby.
Documented
Before and after samples and a visit report for compliance and insurers.
Multiple sites
One contact and one schedule across an estate.
FAQ
Common questions
Anything we haven't covered, put it in the form and we'll answer on the call.
How often should diesel be polished?
For standby fuel that rarely turns over, once a year is a sensible baseline, with a sample test in between. Tanks with a history of water or bug problems need it more often. We'll recommend an interval from your first sample.
Is polishing the same as tank cleaning?
No. Polishing cleans the fuel. Tank cleaning empties the tank and cleans the inside of it. Heavy sludge or corrosion on the tank floor needs a clean, and we'll tell you from the sample which one you need.
Do you polish HVO and gas oil as well as diesel?
Yes. HVO is more stable than conventional diesel but still picks up water and dirt in storage, and red diesel and gas oil tanks on farms and sites are a large part of our work.
What does it cost?
It depends on the volume of fuel, how contaminated it is and where the site is. PRICE TO CONFIRM. Fill in the form for a firm quote.
Ready to get the fuel checked?
Fill in the form above and the service team will come back to you with a price and a date.
