On the surface, polyethylene storage tanks might look pretty similar. It’s tough to tell a more robust tank that has been well designed and constructed from a cheap, inferior one. Over the years, we've found that many customers are unaware of the standard for polyethylene tank construction based upon resin properties and testing or they simply assume all tank manufacturers follow the ASTM D 1998 standard.
The ASTM D-1998 standard is a voluntary standard that differentiates the manufacturers that meet it vs. the ones that don't. However, as in any standard there is some subjectivity to how each manufacturer interprets the ASTM guidelines. Just meeting the standard isn't everything though; it's not an all inclusive list. The standard should be looked at as one in many items in a checklist when picking the proper tank and manufacturer for your application.