Water: Free & Emulsified
Over time fuel storage tanks accumulate water and debris for various reasons (rain/leaks, moisture accumulation, etc). Moisture accumulation is the primary cause of water in stored fuel. As the temperature changes inside of a fuel tank moisture accumulates on the exposed walls. To prevent this we recommend customers keep their fuel tanks 75–90% full and utilize desiccant breathers when possible.
Emulsified water is the most common type of water found in tanks. This is caused by water sitting in tanks for a long period of time allowing the water to oxidize and degrade the fuel. The water and degraded fuel then form a dark opaque mixture. This fuel can usually be saved but only with the use of high speed filtration and water absorbing elements.
Free water is common when a large amount of water is introduced to a tank and has only been in the tank for a short period of time. It can also form when the saturation point of the fuel has been reached. Once the saturation point of the fuel has been reached the water will not continue to emulsify and will drop to the bottom as free water.