I like the aquatek just fine. No regrets at all. Matter of fact, I may scoop up another one and rig up a diy manifold to run a couple of my 2.6 gallon tanks soon. I use a 20 oz. tank and it's been running since November so far. I figure about 6-7 months before I need to re-fill it. It runs at roughly 40 bpm with the included bubble counter to give me 30 ppm +/-.
Not sure about the stingray. Did you figure PAR ratings at substrate? DHG will do good in the medium to medium-high range. It will lighten up a bit, much like many other plants with really high lighting, even with sufficient nutrients, IME. Only thing about the stingray I didn't like was the lack of red LEDs. I like a little warm tone, but that's all subjective. Plants do stretch a little more with those reds, though.