It seems every boat on the west coast always has "Hum Bug" kit. It detects bacteria in your fuel. Its available here ... http://www.paulsenindustries.com/index. ... &Itemid=27
Unfortunately you learned the hard way, what poor management of fuel can do - keep the water out, and like JK says, rotate your fuel just like milk at the grocery store. Rotating fuel is sometimes a pain because youre "not allowed to do it"... stability this and that, or senior people say, "thats the way its always been", then all you can do be vigilant for any sign of water.
I don't think there is anything you can do to prevent high filter consumption at this stage. The tanks will have to be emptied and cleaned manually. The slightness residue will promote growth again, you can use a biocide, but get ready to change lots of filters.[/url]