Owners and operators of underground storage tanks want to maintain optimal tank health to ensure the longevity of their equipment and the quality of their fuel inventory.
For those who manage diesel underground storage tanks, the best method for maintaining tank integrity is reducing the likelihood of in-tank corrosion by continuously removing any water present and filtering the fuel. This is best accomplished through use of the HydrX™ Fuel Conditioning System. Unlike other systems, HydrX is designed to collect stagnant water from the lowest point in the tank and filter the fuel to remove entrained water and particulate.
When approaching the issue of a corrosive in-tank environment, there are some key indicators that your current corrosion management program is working to protect your fueling system and underground storage tank.

Removing Water From Your Tank
The first sign that your corrosion management program is working is obvious; you are removing water from your underground storage tank. Once the HydrX Fuel Conditioning System is installed, it cycles through the vacuum and sweep modes. The user can define the time that each mode is running and a number of cycles (1 cycle = vacuum + sweep mode). When no more water is collected in vacuum mode, the system will stop and forgo any remaining cycles.
In the initial vacuum mode, you will likely see higher volumes of water removed. By targeting the lowest point in the tank HydrX can focus on the area where water stagnates and settles, removing the ability for water to hide within the tank.
Cleaner & Clearer Fuel Samples
As the water is removed from the tank, HydrX is also filtering the fuel to remove entrained water, rust, sand, and microbial particulate. It then returns clean fuel to the tank. The result of this process is the fuel in your tank is cleaner and clearer, which means the fuel at the bottom of the tank is as clear as what you are dispensing at the nozzle. This visual check tells you that the corrosion management program is working to protect diesel fuel from degradation and contamination.
A corrosion management program that includes HydrX not only removes water but also filters and polishes fuel. Here we see the progression of fuel samples taken from the bottom of the same underground storage tank at the beginning of a corrosion management regiment:
- Initial sample taken at site survey. The sample is very hazy, there is standing water present and a heavy layer of particulate from the tank bottom.
- Sample taken two months after a tank cleaning and with no conditioning or fuel polishing for 30 days. The fuel sample has less particulate but is still hazy and there is standing water present within the sample. If nothing is done conditions within the tank will continue to slowly revert back to the starting point.
- This sample was taken after the HydrX system had been running for 33 days. Fuel sample is clear with no visible particulate and no standing water.
Maintaining Desirable Fuel Acidity
The acidity of the fuel within the tank is indicative of how corrosive the underground storage tank environment is. One way to determine its acidity is to measure the pH of the fuel. The lower the pH number, the more acidic the fuel is. For tanks that have a corrosive environment, the fuel may have a pH between 4.5 – 6.
After the HydrX system has been in operation for a week or two, we have seen the pH of the fuel within the UST trend towards a pH range of 6.5 – 7. A pH measurement of 6.5 is at the very edge of a passive oxide surface with no ongoing corrosion at all.
You Be The Judge
Adding a HydrX Fuel Conditioning System to your site increases the useful life of your diesel fueling equipment and improves fuel quality. Fill out the brief form below to find out more about HydrX.

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