Custom-built
Ron: Assuming you can't locate one already built to original spec, you can buy stock sizes, as from Ronco, go the LectraSan route, or custom build. We had the replacement tank custom-built for our boat (H37.5), and I thought the price was reasonable and install was a snap because it was identical to the original.We got the line-drawing for the original aluminum tank faxed to us from Hunter parts (Mike Thomas). I faxed that to C.C. Tech in Rhode Island, who gave me a quote within a day or two. 25 gallon tank for our boat, custom-built to be identical to original (but in 3/8" poly) was $375. I think the cost is reasonable and you don't have the headache of reconfiguring your install for a different shaped tank or LectraSan, assuming you don't want to do LS. Our new tank worked fine all this season.C. C. Tech contact info: http://www.gocctech.com/marine/boat-tank.htmPhone: 401-784-6168 Linda Kleinman for sales. Technical questions ask for Bert.They are in Rhode Island, so shipping will be a tad pricier for you, but ask. Do not delay this project!