Or...... whatever you do, don't be closed-minded to the point of ruling out cool tubes because you made the mistake of valuing your time below minimum wage. Took less than one minute to plug in the bulb, plug in the ballast, plug in the duct, and turn on the light. When I change from MH to HPS, less than 30 seconds, or if a bulb were to burn out. If I have to pick up and move, my entire light and air movement system can be disassembled and removed without a trace in less than 5 minutes. I've done that 3 times already. Only want one light for veg, can take one out in less than 1 minute. Want to move your lights up and down, you can do it with a finger. Want a different angle from the lights for better coverage, you can move them.Want to use them in a closet, then a tent, then back to a closet, then a friends garage, you can move them around easily.
So cheap DIY PLUS 40 hours of your labor over the first years or
cool tubes and about 1 hour of your labor over the first years.
I have nothing against DIY cool tubes. I was ready to try making my own until I learned more about them and knew I'd have to move around. I just apparently value my time more than Nick does and am open-mineded enough to know different options fit different people's lives differently, so "my way" isn't necessarily "right". For me, cool tubes were a much cheaper, flexible, and better option over the life of product. Whatever works best for you. Nick's ingenuity and skills in making a cool tube may be your best option.
(Yes Nick, I admire your DIY cool tube and say great work. No need to pee on my parade to make yours look better.)