heat in a 400watt grow box

I know this question gets asked 10 times a day, but I have a 3.3.4 grow box with 400watt mh/hps. I thought I had it all covered with 2 - 2x10 passive intakes at the bottom, and a 170cfm fan pulling through a filter and the hood. Also I have a small fan inside moving air around. My temps are at 77 degrees but the light is almost to the top of the box,and I cant really feel any air being pulled into the filter. I would like to keep the light closer, plus I will run out of room once they go to flower.
Can I simply get a better fan say a 6 inch 424cfm fan. That would more than double my cfm. I can get the fan for like $100 and thats not too bad if it fixes the problem. Just wanted to check before I buy it. Thanks.

The 170 cfm fan you're talking about, is that the cheap ass fan that looks like a coffee can? The 424 cfm centrefuge fan you're talking about would be great, also buy a speed controler.

Punk said:

The 170 cfm fan you're talking about, is that the cheap ass fan that looks like a coffee can? The 424 cfm centrefuge fan you're talking about would be great, also buy a speed controler.

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No its not a booster thing, its a growbrite inline from htg. Ill probally get the 6 inch 424cfm from them too. Thanks.

i dont think your problem not there is one with 77 temps is not the exhaust you have but maybe if you dont have an air cooled reflector with glass, that helps alot, not only is it cooler it can be closer so its double whammy, another solution would could be a liquid cooled heat exchanger, i want to do this myself, its where the hot exhausted air is passed through a grill cooled by water which is apparently 20x more efficient than just air cooling, so now you have almost cold air coming out, i think this way would be ideal, no heat issues, and everything can be self contained, just my two cents....

trader54321 said:

i dont think your problem not there is one with 77 temps is not the exhaust you have but maybe if you dont have an air cooled reflector with glass, that helps alot, not only is it cooler it can be closer so its double whammy, another solution would could be a liquid cooled heat exchanger, i want to do this myself, its where the hot exhausted air is passed through a grill cooled by water which is apparently 20x more efficient than just air cooling, so now you have almost cold air coming out, i think this way would be ideal, no heat issues, and everything can be self contained, just my two cents....

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Its is a sealed Hood with glass. The Hood is cool to the touch. I just don't think its clearing out the box fast enough. I'm gonna go with a bigger fan. I'm gonna check into those water cooled fittings too.

Well I realized the problem. The air comming out of my exhaust is like 80 degrees, and it vents into my room(9x9). Well it made the temp in my room go from 68 to 79 in about 2 hours, so there was no way of cooling the grow box any more than that right. So I have to find a way to exhaust outside. So much for keeping it low key.

Well I ran my exhaust outside of the room, and bingo, my temps inside the box are like 73degrees with light on, and like 68 with it off. Plus there is even less noise in the room now. Insulated ducting really helps with air noise.