I've been using the Racor 5GPM (RFF8C) to filter raw WMO into a 55-gallon drum holding tank (until I get my filtering station built), and I find it pretty frustrating. It will hold up to 1/3 of its volume in water just fine, but there's no way to tell when it water reaches this level as it is underneath WMO...when I go to pour out the raw WMO on top, of course the heavier water underneath always comes out first....so when I try to decant the water into a waste container, I always end up losing most of the raw WMO on top as well. I tried using a hand pump to skim off the raw WMO sitting on top of the water inside the Racor filter, but that was frustratingly slow and tedious.
Not to mention that I am only obtaining about 1/10 of the WMO from my raw mix from my free oil supplies...I've switched to filter socks & 5-gallon buckets instead, and they work MUCH BETTER and quicker. I'll keep the Racor filter for small quantities of suspect diesel or other fluids that are more viscous & transparent than raw WMO.
Just so you don't get your hopes up on that Racor filter. Of course, it may help to heat your raw WMO supply first to around 100-125 degrees, to make it more viscous and easy-flowing through the Racor funnel filter...otherwise I suspect you'll get quickly frustrated as I was.