Difficulty cooling room

I have a shed that I'm using half of to make my full season room (veg/flower). I have a space sealed off measuring 54"x30"x79".
I've got a Hydroplanet 600w MH/HPS w/ digital dimmable ballast (250w, 400w, 600w, super lumen)
2 x 6" inline centrifugal fans 440cfm w/ built-in speed controller
The room is wrapped in Panda film and I sealed it by making a sized pvc frame, and attaching two tarp zippers for doors. I have my exhaust hanging on bungees, duct running through the top of my mylar door at 2 o'clock, and connected to my vented hood which is open on the other side to allow my room to vent. My intake fan hangs identical 2' to the left, and runs duct through the door at 8 stacked under a passive. There are two passive intakes/exhaust located at 8 and 4 o'clock as you face the door. I am having trouble with the room temp not dropping below 85 while the light is running. The shed does receive an ample amount of sunlight so I'm considering putting banana leaves on the roof, and tying them down to help with another layer of insulation. Any other ideas? Mahalo

I know this is common sense, but sometimes the obvious is overlooked, so it is worth asking.
Are you running your lights during the day or are you having your lights off period during the hottest part of the day? I have a similar problem with heat in a concrete garage and if I have lights on in the afternoon I struggle to get temps down, so I have lights off from 10.30am - 4.30pm during veg and 7am-7pm in flower.

My light schedule is very similar at 18/6 for veg with the lights coming on at 5pm and turning off at 11am, and 8pm to 8am for flowering. I found that if I run my exhaust fan slightly higher than the low setting, and dial my ballast down to 250w at 36" I can get a consistent 79F all night. I don't have any equipment to check my fixtures output, but would the distance of 36" on a 600w bulb dialed down to 250w in a vented hood cause serious stretch?

Sorry, but I cant help you with hps as i use store bought led bulbs. My stealth cab is too small to use a hps in as I hardly have any room height wise.
I just thought I would ask about lighting times as sometimes the simple answer is staring you in the face. I hope another member can help you out. Good luck.

I also grow in a shed, but luckily mine has a crawlspace. Before I bought a portable a.c. I cut a hole through floor and ran my intake ducting through hole because the temps in crawlspace were several degrees cooler than outside air. And like some others guys have suggested, try to set your light cycles to run during coolest times of the day. Good luck.

Kasuti said:

I also grow in a shed, but luckily mine has a crawlspace. Before I bought a portable a.c. I cut a hole through floor and ran my intake ducting through hole because the temps in crawlspace were several degrees cooler than outside air. And like some others guys have suggested, try to set your light cycles to run during coolest times of the day. Good luck.

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Mine has a space of about 4"- 6" underneath it because it's on some sunken cinder blocks. I'm going to try out this method because it's been sitting in the back of my mind I just needed the push I guess lol. Mahalo

Donkeyfresco said:

Mine has a space of about 4"- 6" underneath it because it's on some sunken cinder blocks. I'm going to try out this method because it's been sitting in the back of my mind I just needed the push I guess lol. Mahalo

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One thing I would highly recommend is spraying a fungicide and an insecticide first to kill any unwanted critters and fungus that may be hanging out under there.

Kasuti I figured it out lol!! The roof on my shed has two 1"x26" gaps between the top of the wall. I'm going to construct a cardboard box with a 6"hole on one side, and a 1"x26" slit on the other. Screen the slit and seal it to that gap. Baddabing should work. Lol