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36"x20"x62" Tent with 250/400 Watts of HID?


Well-Known Member
Ok guys, I am thinking of putting together a little veg tent, maybe grow some autos in it if I get froggy. I am set on a 36"x20"x62" tent because it's literally all I have the room for. My ambient temps are around 72 degrees. In my 4'x4' tent with an air cooled HID I am running 79-80 degrees in the tent with my CanFan running about halfway.

The light I am looking at is a Sun Systems Digital 250/400. The hood/ballast/light are all one piece and it is not air cooled, seen here:


For this to work I would need to use a T splitter right before my fan's intake to split and exhaust one 6" exhaust ducting coming from each tent. My fan is rated at 420 CFM so I don't think this will be a problem, although it is honestly less than ideal.

What I want to know is if I will be able to keep temps at or below 80 degrees with this setup running 250/400 watts? I know all this is a great big hypothetical that no one can truly answer with 100% accuracy, but I am hoping to hear from people who have run similar lights. Who cares to take a stab in the dark? Step right up!


Well-Known Member
I got a very similar one from Hydro farm and have used it off an on for 17 years. The worst problem is they are heavy as all get out and when you hang it all the weight is on the one side. And the second problem is the heat. Other than that mine has been great. Once I upgraded to 400W I had nice dense fully mature flowers.

I used to grow in a small self made cabinet and that does make it hot. The upside is it is a small volume so it doesn't take a large fan to vent it. I was able to do it running a handful of computer fans. That said I would not run both tents to the same fan. They will be very different environments and controlling one probably means the other is not optimal. When you upgrade do it right and set up a second tent in its own right.

If you want to use one filter then I would set it up with an intake fan into the veg box, connect the 2 tents with minimum 6 inch flex tube ( I would use 8 inch) and vent the bloom tent through the filter. Then run the speed on the vent fan so it is pulling slightly more than the intake fan so the tents are running a little bit negative pressure so all venting is done through the filter.

That way you will likely have an easier time controlling the 2 tents. If you do a "Y" spliter the flow dynamics are unpredictable based on multiple factors and you could end up over venting one and not venting the other enough. Then you need to start adding baffles and it gets out of control. It can work but I think the simplest easiest and cheapest is placing the tents in series and running a single intake and single vent.

Best of luck!


Well-Known Member
The reason for splitting the fan is because I have one exhaust exit point and adding another would make it look a bit suspicious. There is really no good way to connect the two tents unfortunately. I am still in the planning stages and haven't gotten any closer to figuring out the light situation. I have an extra exhaust fan plenty big enough to vent the 2nd tent when I get it, perhaps I can put the splitter after both fans. I will have to experiment a bit.
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