Considering that you will have a huge aquarium for a stingray, I'd plan ahead and use a wet/dry sump and put my heater in there.
My largest aquarium right now is only a 75 gallon, and I am not using a sump, but had I planned better, I would have installed one inside the cabinet. Too late now since I can't get anything large enough inside the doors.
I do really like the stealth heaters. Bought my first one a few weeks ago and will never go back to crummy breakable glass heaters.