Upgrading to fans, HPS, mylar, and carbon filter

Hey guys, very new here, but i have a couple questions. Right now i have a dresser that i have converted to a growing cabinet, but its too small. I am thinking about upgrading to a bigger cabinet with a 400W HPS/MH lighting system with a coolable hood, 2 6" Duct fans, a DIY carbon filter on the outlet fan, and lining the whole new cabinet with Mylar. So my dresser is pictured here, but i have some more questions.

Say i got a setup like this:

http://cgi.ebay.com/DIGITAL-400-watt-HPS-MH-GROW-LIGHT-SYSTEM-400w-AIR-COOL_W0QQcmdZViewItemQQ_trkparmsZ65Q3a12Q7c66Q3a2Q7c39Q3a1Q7c72Q3a1205Q7c240Q3a1318Q7c301Q3a0Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem1c0897e9c6QQitemZ120403257798QQptZLHQ5fDefaultDomainQ5f0QQsalenotsupported

Would i need to set up two fans? One blowing into one end of hte light, and another sucking out the other end, or just one sucking either in or out?

Also, the ballast says it operates both HPS and MH, but it doesn't say "switchable ballast" like most other ones i've seen. Why is this?

http://cgi.ebay.com/6-inch-INLINE-DUCT-FAN-exhaust-BOOSTER-vent-blower-cool_W0QQcmdZViewItemQQ_trkparmsZ65Q3a12Q7c66Q3a2Q7c39Q3a1Q7c72Q3a1205Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem1c0803615bQQitemZ120393523547QQptZLHQ5fDefaultDomainQ5f0QQsalenotsupported

that is the fan(s) i would go with, then some 6" ducts, but i am wondering if you guys think that is a good deal, coming with the ballast, air-coolable hood, HPS and MH bulbs, and if the whole setup would be a good idea.

So my main questions, how do you set up the fans for cooling hte HPS, is that first eBay link a good deal, will that ballast truly work with both HPS and MH, and if i only put a fan blowing in on the HPS, how do i set it up, and any other info is welcome.

Thanks guys, that last picture is of my baby i have going right now, its 4 weeks through flowering stage and just getting too damn big for the cabinet haha

so i'm thinking about getting that HPS setup with a duct and a fan pulling air out of the cabinet through a carbon scrubber, then on the other side of the cabinet get an additional fan sucking air in and blowing it directly on the plant with no duct. This would circulate air, take care of the HPS's heat problem, get rid of the smell, and also blow some air on the plants stalks to strengthen them.

Something like this: (yellow is fans, green is scrubber). What do you guys think?

That hps setup looks ok, htg supply are a reputable company, I've not dealt with them personally, but have heard good things about them on here.
The way you have thought to set it up is ok, but could use a couple of tweaks.
Cool the light on it's own, separate from the room with it's own intake and exhaust, going intake--->light-->fan>exhaust and it will be more efficient than if it's sucking warm air from the growroom.
Use the second fan as the rooms exhaust, going filter-->fan->exhaust and have a passive intake (a hole which air can pass through but light cannot) slightly smaller than the exhaust, say 5-5.5" to create a bit of negative pressure and stop odour leaks.
An oscillating fan will move the plants more and give better circulation than a fan blowing in one direction all the time.
I would steer clear of duct booster fans, they don't move a lot of air on their own, especially if they have to move it through ducting or a filter. Get a centrifugal fan, like this one http://cgi.ebay.com/New-6-Inch-Inline-Exhaust-Cooling-Duct-Fan-Vent-Blower_W0QQitemZ280278994464QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4141ee0e20&_trksid=p3286.c0.m14&_trkparms=65%3A15|66%3A2|39%3A1|240%3A1318|301%3A0|293%3A1|294%3A50 . It doesn't need to be as powerful as that, it's just an example of the type you want. A 4" might be sufficient, depends how big you make the box and how close to the ambient temperature you want the room to be.
Also some digital ballasts simply detect the type of bulb being used and run accordingly, the only difference is the ignitor, a hps needs one but a mh doesn't

thank you for the reply. Could i have the HPS's cooling just go straight across, with a duct on left side, then light, then a duct on the right side with a fan mounted right on the outside of the box, sucking air out?

Then for the rooms exhaust, would another fan mounted just on hte outside of the box (similar to the light's system), again sucking air out, with the carbon filter attached to the back side of that? Going fan-->exhaust-->filter?

Thank you for the ideas, i'm thinking 2 of these for the HPS cooling and room cooling, and then a small oscillating fan sitting somewhere in the box:
http://cgi.ebay.com/4-Vortex-Centrifugal-Inline-Exhaust-Fan-Duct-Blower_W0QQcmdZViewItemQQ_trkparmsZ65Q3a12Q7c66Q3a2Q7c39Q3a1Q7c72Q3a1205Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem5ad1590173QQitemZ390059327859QQptZLHQ5fDefaultDomainQ5f0QQsalenotsupported

In the picture oscillating fan isn't pictured, but again fans are yellow, filter is gren, HPS is red and the passive intake is blue, not to proportion since it's got to be smaller than the duct the fan is pulling out

http://cgi.ebay.com/NEW-MINI-TOWER-DESK-FAN-COMPACT-COOL-OSCILLATING-TIMER_W0QQcmdZViewItemQQ_trkparmsZ65Q3a12Q7c66Q3a2Q7c39Q3a1Q7c72Q3a1205Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem2301ba672dQQitemZ150352848685QQptZLHQ5fDefaultDomainQ5f0QQsalenotsupported

ooooh, that fan looks just about perfect to me

ahahah nice its growing in a mop bucket LOL!! just come out bigger and better good luck sir!

DownForTheCause said:

thank you for the reply. Could i have the HPS's cooling just go straight across, with a duct on left side, then light, then a duct on the right side with a fan mounted right on the outside of the box, sucking air out?
That's exactly the way it should be, try to set it so the ducting will be as straight as possible in the position the light will spend the most time.
Then for the rooms exhaust, would another fan mounted just on hte outside of the box (similar to the light's system), again sucking air out, with the carbon filter attached to the back side of that? Going fan-->exhaust-->filter?
That will work fine. Most fans will work better sucking through a filter rather than blowing, but the difference will be small as long as the cfm ratings on the fan and filter are about the same.
Thank you for the ideas, i'm thinking 2 of these for the HPS cooling and room cooling, and then a small oscillating fan sitting somewhere in the box:
http://cgi.ebay.com/4-Vortex-Centrifugal-Inline-Exhaust-Fan-Duct-Blower_W0QQcmdZViewItemQQ_trkparmsZ65Q3a12Q7c66Q3a2Q7c39Q3a1Q7c72Q3a1205Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem5ad1590173QQitemZ390059327859QQptZLHQ5fDefaultDomainQ5f0QQsalenotsupported
That is pretty expensive, and the cfm rating isn't that high for the size. It will do the job, but I'm sure you can find a better deal. http://cgi.ebay.com/New-4-Inch-Inline-Exhaust-Cooling-Duct-Fan-Vent-Blower_W0QQitemZ280278994328QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4141ee0d98&_trksid=p3286.c0.m14&_trkparms=65:12|66:2|39:1|72:1205|240:1318|301:1|293:1|294:50
In the picture oscillating fan isn't pictured, but again fans are yellow, filter is gren, HPS is red and the passive intake is blue, not to proportion since it's got to be smaller than the duct the fan is pulling out
Better, but mount the exhaust as high as possible so it removes the hottest air, which will rise to the top.

Click to expand...

The oscillating fan looks ok from the spec and has a nice small footprint.
You seem to have everything covered, keep it up.

haha yes yes i know hte mop bucket was ridiculous, it was only there for a week or so, its got a nice new pot now

and Bob thanks so much for the info, just today itself i've learned a shitload. Any ideas on a material to use for the passive intake or how i could go about constructing it?

And one last revision of the cabinet:

i think you should keep the cabinet as a vegitative room...or to start plants or clones intill the new room is done flowering....but about the setup i think you should get it and dont cool the light just get a air intake and a air outake spacxed far away from eachother around your grow box....if your new growroom is good than it will be big enough to sustain the heat with an intake and outake on the box....keep us updated

It always helps to manage the temperature if you cool the bulb/s. You're significantly reducing the biggest factor in thermal fluctuation and so making it simpler to have a room that remains at a fairly constant temperature.
If the temps are kept within +/- 5 degrees of the ideal (75 light on, 65 off), it minimises stress to the plants and leads to better overall health and possible increases in yield.
Also if the bulb is kept cool, it can be closer to the tops of the plants, maximising light intensity at the bud sites and again, leading to greater yields.
Of course there's no harm in putting the thing together without cooling the light and leaving it running for a while, checking the temps at several points throughout the day with light on and off, to see how much heat you're dealing with.
Unless you have to heat the room during the dark cycle, as I do for a lot of the year, I think you'll look at air cooled hoods rather favourably.
Hope that made sense, I've driven 500 miles since yesterday afternoon to go to a concert, my car broke down on the way home and I had to fix it on the side of the road with my wife lending moral support, it's now 5:45am and I've not been home an hour, but find myself on here worrying about if I'll come across as a bit gibberish...
Nevermind me, test your room out. Happy tokings.

no worries bob, you hvae been beyond helpful. I'm thinking about constructing this cabinet and ditching the old dresser, using the new cabinet for both veg and flowering ,just switching the bulb. Maybe in the future i'll build a strictly veg cab, but for now i think if i construct this it will be 100X better than the dresser i have now.

wow man, i actually just did this same basic thing with my old dresser, lol.

DO NOT buy htg carbon filter your wasting your money get a better one man trust me i bought one from them and i have to buy another one fro ma diff company now becasue theirs sucks balls

Here is how I did mine, 4ft x 2ft x 6ft grow tent. Everything is inside and I pull air through the filter instead of push air out of it. the blue stuff is air not water...