Hey guys, I have a few questions regarding cool tubes, so if anyone has experience using these please give me a shout 
Firstly, do I need a specific tube for a 600W HPS bulb? I don't want to buy one that could potentially shatter.. I already have the bulb, reflector and ballast - none of them being used yet.
Secondly, is it simply connecting an extraction fan to the tube and some ventilation pipe? Just want to make sure I understand the concept fully 
And finally does anyone know how much heat it will save? I run my tent with LED's and my idea is to use the 600! hps during flower to give them a boost, but need it to remain nice and cool where possible.
Thanks in advance to anyone that can help, recommendations, comments everything welcome :Sharing One:
Hey Pal, I run cool tubes so I thought I'd chime in as well!
To your first question, namvet's right; you'll want to size the cool tube to your 600W lights dimensions. However, something to look into (because I'm not 100% sure on this, so I just don't want to mislead you,) I
THINK as long as you have the correct E39 Mogul Base socket on the cool tube, it SHOULD work with your lights. My reasoning behind this is that I'm doing searches for various cool tube brands, including the ones I run, and they are not showing any wattage specific product specs. But they all tout the E39 mogul base; which is the socket your lights plug into. As long as you're correct there; I don't think you'll run into any problems with your light or ballast. Let me double check on this for you with some of our resident AFN electricians.
To your second question, yes they work just like the ducting you'd find on a vented hood or anything else. If you have 6" ports, you can use 6" flex duct and 6" fans. It's more effective to pull the air through the light instead of pushing air through it (much like a carbon scrubber setup.)
To your third question, it depends on your ventilation is setup. If you run the cool tube with it's own fan separately from your ventilation; you can have the intake come from one side of the grow space and exhaust on the other side. That way you're keeping all that warm out out of your grow space. You'll still generate heat; but the amount you'll notice is MUCH less. If your intake for the cool tube is inside the tent; then you're drawing on whatever temperature difference there is between the inside and outside of your grow space.
I think cool tubes are little misleading; some of the primary advantages over a vented hood are usually (and typically) a smaller dimensional footprint, more effective air flow (air flows through a straight shaft cylinder FAR easier than it does bouncing around a boxing vented hood, this allows for less CFM reduction on your fan and technically should reduce the amount of sound and vibration produced, as when air bends around corners, it creates turbulence, which increases decibel levels. They're also pretty light to carry and very easy to store.
The downside of cool tubes is usually the uniformity of the light spread. My cool tubes came with some pretty chintzy add-on reflector wings. They definitely work better than not using them, but compared to my 1000W vented hood; it's a NIGHT and DAY comparison to how they throw light down.
I run iPower cool tubes myself; they seem pretty well built and were under $40 USD. Make SURE you look at the dimensions of the cool tubes on whatever site you're looking at though; they vary greatly!!!
Just something to keep in mind! Hope that helps out a bit bro!