Ryuji, if you want to stay with plastic tanks, then look at the Beseler or Jobo tanks. The problem with Patterson tanks is the flange that extends below the actual bottom of the tank is not well supported. The Beseler tank doesn't have such a flange; the bottom is molded more like a SS tank where the sides turn a rounded corner to form the bottom. Jobo has a flange, but it is wider and well supported. Either tank will take a lot more pounding than the Patterson.(posted 8274 days ago)