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Re: Cleaning fuel and water tanks. How often
Here's an easy definitive way to 'test' your water tank if it needs cleaning: Reach in and FEEL the bottom portion of your tank walls with your fingers. If it feels slimy to the touch when you rub your fingers on the surface, that's a massive bacterial colony.
If so, there are several ways to remove it:
1. sequential/repeated shock sanitizations (4-8 oz. of clorox per 10 gal of tank capacity, let soak 1-2 hours, then flush) until no slime is felt.
2. If failure to remove (as in #1), then mechanical hand scrubbing with detergent and brush, flush/drain/rinse, followed by single shock sanitization.
If tank is aluminum, Lessen contact time for shock sanitization, NO repeated treatments - so get out your long handled scrub brush .
BTW - chlorine does NOT kill most protozoa (oocysts such as cryptosporidium or giardia); nor, and many uncommon pathogenic bacteria. Until about 2010, oocysts were a massive problem in many local US municipal water systems, especially those that drew their water from lakes, reservoirs, rivers, and other 'surface' water.
Maintenance doses of chlorine in excess of recommended water dosages is considered a possible carcinogen - 1 to 2 ppm or about .4 to .8 oz of Clorox, etc. per 10 gallons of tank capacity. The correct dose is that you can 'just barely' smell chlorine in the spigot water.
1. Open tank and look in to see if accumulated debris at the bottom or 'black stuff' sticking to the side walls/bottom in your estimation would fill one Campbell's soup can. If so, clean/scrub the tank. Reason: The typical Racor only has the dirt capacity of about 35 to 50 grams of tank 'sludge' .... about the content capacity of one Campbells soup can.
Debris that adheres to the walls of diesel tank are usually fungal colonies and their products of metabolism - 'resins'. Eventually when the 'residents' of the fungal colony ultimately die and then decompose, the 'stuff' will break loose.
1a. Ive seen remarkable results with (Startron, etc.) "Enzymatic Tank Cleaner" .... but I use it only for 'mild' tank contamination, not massive contamination.
• How to tell WHEN to open the tank for inspection of the internals (other than seasonal maintenance): 'Dark' fuel oil, or the fuel oil has a haze. Method: decant some fuel into a clean glass container and hold it up between your eyeballs and bright white light or sunlight ... any 'cloudiness' is a HAZE which indicates particles greater than ~10ÁM. If you can SEE haze when you 'backlight' with strong white light, you have a massive amount of particles at greater than 10ÁM.
FWIW - when traveling, I usually always do the 'glass/eyeball' test before any fuel enters the tank .... saves a lot of grief, especially in the islands, etc. that get their fuel deliveries from 'barges'. If hazy, I simply close up and look for CLEAN fuel.
Last edited by RichH; 06-23-2015 at 02:10 AM.