[Alan Wheeler]

Alohaboat, that is the first time I have ever seen someone else suggest a totaly sound and sober correctly written statment on fuel.

Dave, AlgaeX is the one of the makers or pushers of the magnetic thingy. I have not read their entire article, but in the first few line there was enough crap to put me off going further. they need to place a magnetic fuel trap on their word processor.
The other fuel doctor wasn't a lot better.
What I have always found is that the ones that are full of the biggest load of crap are they ones that right all the glossy big words. They baffle you with BS and try and make it look like science. They try and make the oil companies look like amatures and that the real R&D is being done by these additive companies. Some even go as far as suggesting that they make some special formulation for NASA or other top govornment agency like the instance of CG and the magnetic thingy.

Alohaboat is spot on with his statment. I say it this way.
If you don't have water, you can't get bug. Keeping water out of the tank is simple. As Gord suggested, that is filtering at fill time. High capacity fuel filters designed for tank transfer pumps are easily available. They are a 10u filter and mainly seperate water and any large crud from storage tanks as you transfer to the vehicle tank.

the next effective area to prevent water in the tank is to have a low depression in the bottom of the tank with a trap that water runs to and can be drained off every now and then.

I do on occasion dose the boat tank with Biocide. But only as a preventitive to ensure Algae does not take hold. I would only ever do this in a tank I know as clean first. I have seen too many examples of tanks being dosed and the boat off out to sea and then a nightmare begins as the algae now floats free and blocks filters up instantly.