Due to the manufacture changing the design of the tank, there is a fitment issue when trying to mate the old bottom (550-0201) to the new tops 550-0611 (75 & 100 sqft), 550-0621 (125 & 150 sqft), 550-0631 (175 & 200 sqft). It is recommended...

415-6001 WATERWAY 2 1/2" Union Nut Manufacturer: Waterway Product Type: Pool Part

550-4407 Tank Body, Waterway Crystal Water, Gray, with Label

805-0227 WATERWAY Oring Manufacturer: Waterway Product Type: Pool Part