HPS in rubbermaid growbox

pacman123

Well-Known Member
I've built the 30 gallon rubbermaid grow box, it will have 12 cfls, but I'm considering buying a 400watt HPS for flower. If I went with a digital ballast and a cool tube, if my grow box was cooled and vented and stayed in the mid 70's with the cfl's, then a 400watt hps with a cool tube and an 80 cfm fan pulling the air away from it should prevent the room from any increase in heat, right?
 

bfq

Well-Known Member
wow that will be a lot of light and heat in that area :o

100 watt HPS should be sufficient for that space and a lot easier to cool.

no matter what type of ballast you use, put that puppy outside the grow.

good luck!
 

Bongulator

Well-Known Member
I think the phrase 'HPS in rubbermaid growbox' translates in Ferengi to, 'Oh crap! Fire! Run!' Heh, just giving you some shit. ;)

The *room* (containing the growbox) will increase in heat, unless you have air conditioning or a heat pump or a fan to move the heat out of the room. But I've lived with a 400-watt light *and* a 432-watt (low profile fluoro) in my room for years, and it's not significant. Actually, in the winter it probably saves a tad on heating (but takes a little extra air conditioning in the summer of course). A beefy computer probably emits more heat than a 400-watt HPS light.

Your fan seems too small though. I cool my 400-watt cooltubed light with a 440 CFM 6" fan that is dialed down to move around 200 CFM. (A 6" fan spinning slowly to move 200 CFM is quieter than a 4" fan roaring along at full speed.) 80 CFM, I dunno, that seems a little light. Doesn't hurt to try it though, as long as you don't let the heat build up and cook your plants. In fact, I'd try it first with no plants in it, just to be safe, and have a backup plan in mind if the 80 CFM isn't adequate.

Also, what kind of fan? Many kinds of fans will burn out their motors if they experience significant back pressure (e.g. if they have to suck against resistance). That's why most folks use centrifugal fans: they are designed to handle that stress.
 
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pacman123

Well-Known Member
It's a ball bearing 120mm 120v PC fan. I've got two passive intakes at the bottom, both about 2 inches in diameter. I'll be putting a homemade carbon filter on the outside of the box, running from the fan. I'll also have a 6" deskfan inside to move the plants and keep the air from getting too warm under the lights.
 

Gmrpr7

Well-Known Member
I would get a 150w hps (maybe a 250w tops) in there. Let me know how it goes cuz your growbox idea is similar to mine.
 

born2killspam

Well-Known Member
The temp would probably rise to the 140's.. It would be impossible to work that while maintaing any decorum of stealth, as well as spending more on ventilation than it would cost to set up a far better chamber.. To use ANY hid, or even more than a couple 23W cfls in there you will need more fan power.. And if you can manage to cool a 150W hps with good stealthy air-flow then you're doing pretty good..
Remember that if you can't just stink up the place then soon enough you'll need to tack a carbon filter on there that will reduce airflow, and raise temps again.. Never forget the 7 P's..
 

{Kottonmouth.King}

Well-Known Member
I have been building a rubbermaid box and I have spent a long time trying to figure out how I want to light it. I have a pretty tight setup that I could run CFL's in but I want the higher lumens of an HPS. I'm pretty sure the 400w would be just too large. My thoughts have been to install a vertical 150wHPS and have a fan directly above it so the heat will be pulled out asap. Also still have some 6500K CFL's for spectrum mixing, I think this type of setup would work but I'd have to keep the plants short cause I would only have about 40" of height to work with. That doesnt include how tall the pots are gonna be or how much distance away from the bulb the plants need to stay.

Keep in mind you height requirements and when you flower how much your plants are gonna shoot up. If you do end up building it with a high wattage HPS lemme know and take some pictures of your steps so we can learn from you.
 
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