Fuel/potable water additives

[Byekurman]

My two diesel fuel tanks hold 150 gallons each. I filled them up around a month ago. I draw off both tanks simultaneously. It may take me a couple months to use the remaining fuel. Should I consider using any particular additive?
I have a similar question regarding my onboard potable water. I draw off both tanks when using them but sometimes I may be at my marina on shore water for a month and the tanks are just storing water. Should I consider using any particular additive?

 

[Comodave]

If you are going through your diesel that quickly then you don’t need add anything. If you don’t use the water in the tank then just pump it out and refill it. You may want to sanitize the water system once a year. Get Peggie Halls book on smells on boats, it describes how to sanitize the system.

 

[FF]

Many folks find using a fuel bug killer is worthwhile.

Switch brands when each type of bug killer is used up

As few boats have a proper sump, any water in the fuel will allow bugs to thrive.

An ounce of prevention beats a tow boat policy.

 

[Pete Meisinger]

I use fuel additive in the fall prior to storage. I add it every year even if my fuel usage that year was not very high.

Potable water? from a tank? Not really likely. I empty, through use, and refill my water tanks several times a year. The water can generally be considered fresh. I add about a half cup of unscented bleach per 150 gallons. You can't smell it and you can't taste it.

But is the water really "potable"? I brush my teeth using it. Occasionally I will wash down a pill with it. We boil corn and cook spaghetti with it. We wash our dishes with it. But do we ever sit down with a glass of it to drink? Never. Do we mix lemonade or make ice tea or coffee with it? No.

Depending on our travel plans we carry about 4 gallons of drinking water and maybe a case of bottled water. Lots of places around here to refill or purchase more.

pete

 

[bayview]

I often drain the water tanks and then flush all the lines before a cruise.
Have been drinking from the tanks for years with no problems because I follow Peggie's process at least yearly.

 

[dhays]

Usually once a year I’ll drain and disinfect the water tanks with bleach. Buy Peggie Hall’s book and follow directions for commissioning your water tanks.

I am happy to drink the water in my tanks. We generally have good water in the PNW.

The OP, I would disinfectant your tanks and then fill and use them. I would not hook up to shore water as long as you have tanks to use. It is easy to fill a water tank and you don’t have to worry about a pressure regulator failing and your fresh water springing a leak. If my system leaks, I’m limited to the max 350 gallons of water I can carry. If a system connected to shore water leaks, the amount is unlimited.

 

[firehoser75]

I am with Dave on drinking the water from our tank. We sanitize the entire system every spring using Thetford's Freshwater Sanitizing system (I have aluminum water tank so don't want to use bleach). I filter the water going into the tank using a good quality water filter (mainly carbon) and use a Nature's Pure QC2 filter system at the galley sink for drinking. I leave the tank empty every winter. I am also fussy about the water source that goes into the tank. Our water is clear, good smelling, and tastes good. Use your water and change it often (don't let it sit).

Fuel additives are a debatable subject. Some insist that no additives are needed, and maybe even a bad thing. Personally, I use Startron Diesel additive and a biocide. These were given high reviews by Practical Sailor testing a few years ago. If you have older engines and are worried about the possible lack of lubrosity due to ultra low sulfer, you could add a small amount of ATF (1 quart per 200 gallons?) to increase the lubrication, but for most engines probably not needed.
Just buy your fuel from a busy, high volume trusted station, and keep water out of your tanks (change deck fill O rings, etc.).