Keeping stingrays in pond/pools

[Cowturtle]

I was wondering which of these two pools would be better for a single male leopoldi and a pair of orbignyi I prefer the rectangle but I'm not sure if I would be able to keep the leopoldi in there long term.

59X59 rectangle 415 gallon
http://www.sharkandreef.com/shark-pond-pool-415-gallon-capacity-59-x-59-x-27-6/

78in diameter circle 663 gallons
http://www.sharkandreef.com/round-koi-pond-show-tank-78-7-x-31-5-663gal/

For filtration I was thinking of a 55 gallon drum as a wet dry.
If anyone has other recommendations I would love to hear them.

 

[Raynado]

I've used the circle pool in the past as temporary housing for my rays, and it worked fine and I wasn't concerned about the material being torn apart. The price difference isn't far apart so I would recommend the circle as it offers more water volume and a bit more space. As for filration, the drums will work as I did the same. Again, I only housed my rays there for 6 months so not sure about long term usage

 

[SHARK13]

I have one of the square ones. It's nice size. I did twin 55 gallon barrels on the filtration side. With a prefilter before the first barrel. First barrel is filled with K1 2nd barrel is heat exchange. If you get either if them do yourself a favor and throw away the bulkheads they come with and buy good bulkheads. I foolishly trusted them and I paid the price. One of mine cracked a month after I got it setup. I came home to about 250 gallons of water on my basement floor. Was not happy. Had to change the lower bulkhead on the fly water pouring out of it... draining the pond was not an option for me as I already had a few large fish in there...