Don't get me wrong, I love my qb's just they are better suited for my smaller 1x2 and 2x3 cabinets..... the 315 is perfect for a 3x3 so for a 5x5, I would go with 3 315's or 2 630's
I'd say ~10F cooler than a hid though ~5F warmer than leds..... I run both of mine with cool tubes hooked to its own thermostat so I stay within 75-80F and can get them real close if I wanted. In fact, right now 1 of the clones cola's is ~10" away so i'll need to raise it again for a more appropriate 18" before she gets light bleached
The conversion kits are the way to go even if you have to buy a hood:
6" ipower hood = 45.99 - probably cheaper on Craigslist
Hydrocrunch 315 conversion kit (ballast and socket adapter) = 97.85
Protopia 315cmh bulb - 49.98
I already had the hoods with 2 more in storage so 1 month I picked up the conversion kit and the next, the bulbs so it was easier on my wallet. You could also get a complete no name 315 cmh kit for $178.00 (x3 = 534.00) or a 615 cmh without the bulbs for $224.65 (x2 =449.30 + 100 for 2 bulbs = 549.30) on Amazon.....i'd have to run the numbers though I believe that's ~half the cost to use decent leds for the same space
Strrrreeeetttttccchhhhh!!! How far away is your light?