Help setting up grow cab - Heat

Hey all,

I could use some advice...

I'm trying to get this cab setup but am experiencing issues with heat. High 80's which is way higher than ambient, temp builds throughout the day. I had a carbon scrubber hooked up at first, that was even worse...

Details: Cab is 3' x 2' , 600w aircooled, 6" 400 cfm fan on a dial, I drilled a bunch of holes for passive air intake. It seems to have some negative pressure... I don't run the fan full speed cause it is loud as hell... Any suggestions please?

Is your ballast adjustable? If so cut it in half... That is way more light and heat than you can handle in 6 square feet..
Most ppl shoot for about 50 watts psf or 300 watts in your case.

Yeah, I was thinking that, but this is what I have to use. The ballast does have a dimmer feature! I am using it.

But I am unsure if that does more harm than good? I read about lowering the amps can potentially change the spectrum?!

I wonder if I put the scrubber in the cab, on the other end of the hood, I could run the fan at full instead of 3/4th. Then maybe 75% on the ballast power instead of 50%. 100% is definitely too much, I think the ventilation is fine, but 100w per sq ft.. does that usually require AC?

I dunno. Bleh.

The reason your fan is so loud and inefficient is because you need to increase you passive intake to make sure that the total area of intake holes equal to two to four times larger than the exhaust. This will prevent your fan from over-working and will help your ventilation system achieve proper suction. The bends in your ducting are also making it difficult for you fan. To calculate check here https://www.rollitup.org/t/ventilation-chart-and-calculator.419563/

2nd what are your ambient temps outside your passive intake? With proper ventilation you still need around 10° colder ambient temps with a 600w HID. Your answer to that will tell you whether you need AC or not.

Also you will find more success with temps if you setup a closed cooltube. You can pull it off with your fan just pull the fan out of the cab and hook up a Y splitter, 1 line pulling hot air through your filter inside the cab and the other pulling through the cooltube. (Your cooltube needs it's own intake port.)

^^^
Thanks for the advice! I ended up cutting a 12" x 12" square in the bottom for ventilation, works much better. I also mounted the carbon filter IN the cab for future use. It's getting colder here day by day so I hope I'll be good, ballast is at 75% currently but they're seedlings anyway so it works. I'm hoping as I raise the lights the ventilation will work better as well.