Thanks or the input on the Alpine 11, much appreciated. Another cool thing about using computer cooling stuff is that it's designed to dissipate heat in a small confined area, so I would imagine that using them in a larger (relatively) area like a grow would only make them more efficient.
That guys setup is awesome, especially since it's a DIY style water cooler. I was thinking something more along the lines of the Cooler Master Seidon (http://www.coolermaster.com/cooling/seidon/seidon-120v/). But at $50 or 5x the price of the Alpine I don't know that it would be worth the additional performance unless you had some really nice COB's that you wanted to keep safe and cool.
That Cooler Master looks pretty neat. I would say its not worth the extra cost over the Alpine 11 Plus unless you were running the COB real hard (higher amperage). The Alpine 11 Plus keeps my 3070s @ 1.4A running pretty cool, heatsink isnt very warm to the touch, never measured actual temp with IR thermometer or thermocouple though.
But if you really wan to use a water cooled CPU cooler, dont let me stop you from trying it. It is a pretty neat concept.