Precision Fuel Solutions
Tank and Fuel Care
Modern diesel and gasoline begin to break down as soon as they finish the refining process. This degradation can be slowed by adding stabilizers and storing it carefully, but it can't be stopped. As the fuel degrades it will develop larger particles which become heavier than the rest of the fuel and these particles begin to settle out. This much is true for both gas and diesel. The difference is that old diesel can usually be fixed while gasoline usually can't. While these particles are still suspended in the fuel they can easily be filtered out. Whenever the fuel is just sitting in a tank, like it usually is on pleasure boats, the particles are settling out and forming a layer of sludge in the bottom of the tank. Add a little bit of moisture to this and possibly some microorganisms, mostly types of bacteria and fungus that eat and degrade diesel and excrete acid, and you have a diesel tank problem.
In my experience, about 90% of diesel tank leaks come from the inside. In contrast, about 90% of leaks in gas tanks come from the outside. The leaks that start on the outside of a tank are usually because of foam, insulation panels, or some other material that will absorb water, especially salt water, and hold it against the tank. On a steel tank you may end up with holes in the top or side just from a small deck leak onto the tank. Another thing that can cause especially an aluminum tank to leak is electrolysis. If an aluminum tank is touching a copper pipe or sitting on a brass screw it could corrode and develop a leak in that spot.
Due to the way diesel breaks down today and how welcoming it is for microbiological growth, the vast majority of dirty, leaky tanks are diesel tanks.
So, what does all this mean to the pleasure boat owner?
Well, first, if your boat is more than a couple years old, it means you should probably try to get some idea of what the condition of your tank is. Unless you are the original owner and have added biocide to the fuel consistently, chances are there is microbiological caused debris or even active growth in a diesel storage tank, on a boat or otherwise. A bottom sample from the lowest point of the tank and an examination of the fuel filters will paint a fairly accurate picture of the tanks internal condition. Other factors such as age and usage of the tank can help fill in the blanks.
Ok, so the tank looks like it could use a cleaning. Now what?
Now we decide what method of cleaning will work the best for this tank and the boat owner. >>>>>>>>>>>>
Now that the tanks clean, how do I keep it that way?
Before we worry about that, now that the tank is clean it should be thoroughly inspected for corrosion and other issues such as obstructed pickups, cracked welds, or anything else out of the ordinary. An educated decision can now be made as to whether some sort of repair is needed.
Ok, now how to keep it clean!
You probably can't, not completely anyway. You can however, vastly extend the time between cleanings.
First and foremost, never let fuel sit in the tank without treating it with a good biocide such as Biobor JF. Biological growth in your tank is the last thing you want! Adding a good fuel stabilizer like a Stanadyne product will help too, especially over the slow winter months. Another good idea is to keep the tank fairly full over winter to cut down on water from condensation and check that the fill caps are sealed. One other thing that will help keep the tanks clean is an on-board fuel polishing system. If the right polishing system is installed and plumbed correctly it will keep the fuel so clean that there are virtually no heavy particles to settle out.