I bought a JohnDow JDI-AFT106 (106 gallon) fuel tank about four years ago and based on my experience with that system bought another JohnDow JDI-AFT58LP (58 gallon) fuel tank about 18 months ago. The 106 gallon tank has a provision for a separate DEF tank but I doubt that's in my future. JohnDow systems use very nice, good quality hardware, fittings, pumps, etc., and the same isn't true for the Chinese knockoffs such as systems from VEVOR and similar. On the upside for most of us, we're not filling up every day, 260 work days a year, so how good does this stuff have to be? Probably not that good to be a significant upgrade over 5 gallon containers.
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Every gas station around here has off-road diesel and three types of on-road diesel (in the winter months). As for water in the fuel, I've never had that issue in close to 25 years of owning and operating diesel equipment. I guess I'm just lucky.
When I think about how much money I've spent on diesel over the years, and continue to spend, the cost of a decent fuel storage/dispensing system pales in comparison. The cost to fill up that 106 gallon JohnDow storage tank is about 1/3 the cost to buy that tank. I like nice, purpose built things and not cobbled together stuff. Some like putting time and effort into making something from nothing and I get that. I do that all the time, mostly with steel, and particularly when good options are few and far between, but that's simply not the case for fuel storage and dispensing. There are numerous decent to excellent turnkey systems available.