After I’d delivered my Grand Banks 32 to her new Florida home, her whole schtick changed—she went from being a true long-legged cruiser to the maritime equivalent of a couch potato, with a travel regimen featuring whole weekends dockside (for dealing with maintenance projects left unaddressed during the jaunt down the Intracoastal Waterway from Maryland) and seldom more than a few hours underway on any given trip. While this kind of thing nicely reduces fuel-related spending, it’s got a downside: the lurking threat of microbes.

More to the point, because Betty Jane‘s single 135-hp Super Lehman is so lightly used and fuel-efficient, burning well under 2 gph at cruise, it’s not unusual for her two saddle-type fuel tanks to sit full or nearly full for months. We all know what can happen to diesel fuel when it twiddles its thumbs under such conditions for too long: Water condenses and pools, producing a homey environment for algae and other microorganisms. Then, when you eventually fire up the ol’ powerplant on some misbegotten day, the primary fuel filters clog with stringy black gunk, and a messy, sometimes dangerous impromptu shutdown ensues. Yikes!

Of course, fuel-contamination issues haunt other boaters besides me—for instance, PMY editor-in-chief Richard Thiel (see Magnetize Your Diesel Fuel). And the market’s loaded with fuel additives and various fuel-purifying devices that purport to help or cure the problem. But I was vaguely uncomfortable with many of these products as I considered my own situation, primarily because the manufacturers marketing them were unfamiliar to me. So when Walker Engineering recently offered PMY a product called the Walker AlgaeSep for testing, I was all ears. Walker’s the ISO9001-registered company behind the Walker AirSep, a closed-crankcase-type engine-room air-cleaning system you see on most new, diesel-powered boats these days. Would I like to give an AlgaeSep a try? Heck yes!

As soon as my unit arrived via UPS, I bulkhead-mounted it in my engine room, between the genset and the portside fuel tank, with the understanding that Saunders Yachtworks, Walker’s dealer in Panama City, Florida, would install pickup tubes and fuel returns, run hoses and affix valves, and do all necessary electrical work soon after. PMY would pay for all parts and material. Labor would be gratis.

This article originally appeared in the January 2007 issue of Power & Motoryacht magazine.