im thinking of putting the 150 hqi in a Original nanocube hood. the ballast crapped out, and why not go big? I can get the light in just fine, jsut heat is my worry, dont wanna melt the hood. Would 2 fans be enough to cool this? i was thinking of one blowing in and one sucking out? or should i just have them both sucking out? also, with the bulb cover, would that be fine, of course i will need to put glass up too, but will the plastic cover still be fine, and wont melt?

This is not a good idea unless you go with a tested retro kit. also, you will need to replace your glass with a UV filter glass. MH produce lots of UV that will kill you live stock.

You will need at least 4 fans. Heat will be an issue both in the hood and in your tank water.

Look at this retro:
http://www.nanotuners.com/product_info.php...products_id=396

or just go for the whole new hood - one designed for a MH, plus it's cheaper:
http://www.nanotuners.com/product_info.php...products_id=407

I wouldn't recommend it in the 12g OG/DF for a couple of reasons. One reason is the splashguard isn't sealed so any parts installed are going to be subject to corrosion and moisture. Also, you're more than likely going to melt your splashguard. This was even an issue for us in 12g DX canopies WITH plenty of ventilation. The 150w HQI bulbs just put out A LOT of heat.

Even if you were to consider going with an HQI install into a DX hood instead it'd probably make sense to go with the 3.6 LED retro instead in a DX hood since the cost would be the same, but with the benefits of LED lighting.

Just my two cents.

ok, well i need to do something, i tried to put endcaps in with a 24 watt bulb and it wouldnt fit. the endcap made it too long as the orignal hood had a few wires that go in the bulb. the ballast went bad so i want to upgrade the hood. i guess ill make a hang on tank fixture