Hi guys, planning to get a 600gallon pond as an upgrade for my rays. I plan on ordering it from this website. http://www.jacksonvillekoisupply.com/6-Deepwater-Koi-Show-Tank-DW6.htm. For $300 and roughly 650 gallons, I'd have to say this is an excellent deal. The only catch is that the pond is made of 'very strong pvc material'. I planned to add pond liner to the pond as insurance since I'm keeping rays in there. Would this work guys? Has anyone had experience with a PVC-type pond? Any advice is appreciated! Thank you!