After 190 hours of polishing, at a very high flow rate for our tank, 72GPH @ 2 micron, our $10.49 Racor 900 filter will likely go well over 500 hours before needing replacement. The piece of mind is that I know most every chandlery carries them, the Racor Turbine filters are perhaps the most popular marine filter made, and I usually keep two-three extras on hand too....
Our filter actually cost about the same as two gallons of diesel and will likely go well past 500+ hours if I needed it to. I still swap them every season. I initially intended to filter to 10 micron but the filter came with a 2 so I left it in and now am filtering to 2 micron instead. My primary engien filter, a Racor 500, is still a 10 micron and the on-engine Westerbeke factory filter is a 15 micron.
Polishing filter and on-engine filter @ 190 hours at 72GPH and 2 micron (engine run time 111 hours);
When I designed this system I had the tank built specifically for it with its own dedicated pick-up and returns for the polishing system. The pick-up sucks at the dead bottom of the tank and at the absolute lowest spot and is a mere 1/8" off the bottom. The polishing return has a dip tube returning the fuel below fuel level to minimize foaming and also it returns to a separate chamber in the tank. The polishing system is run whenever the engine is and also can run separately.
I chose the Racor 900 because I like the filter, know it inside and out, and I can see the condition of the fuel in the bowl. It is more expensive than some other filters you can buy, but is still short money compared to a single "professional" tank cleaning/polishing, which never gets it fully clean anyway.
