I have always used a drum but wanting to get a 100 tank with 12 volt pump. I like the idea of a aluminum tank for no rust but they are pricey. How big of a issue is rust in the transfer tanks? I would use 150-200 gallons a year. Proably passed uo a good deal on a 100 gallon tank for $150 that I am kicking my self about. It was an hour away and pic looked ok but wondered what it was like inside.