HPS ventilation question

niggles8

niggles8

New Member
Hey everyone.
First grow here
Been doing a bunch of research on these forums learning what I can to get the most out of my grow.
I am stuck here with a question though, was hoping someone could help me out.

I have a 12x10 bedroom that is not in use and practically empty. I am using about 5x5 of it as a grow area. Currently using CFL's but thats not going to cut it soon. I want to get a 400w HPS system with a MH bulb. I was wondering if in a room that big, AC usually at 70-74f, would I need ventilation for the light?

Thanks for reading!
 
justugh

justugh

Well-Known Member
venting yes always

venting does 2 parts .............removes the heat from the room and adds fresh CO2 /O to the air for the plant to use

during the lights on the plant needs CO2 and then coverts it O and u need to remove that converted and replace it with fresh Co2
during the lights off the plant wants O and converts it into a Co2 gas but this is not useable co2 for the plant and needs to be expelled


with a room that big ..............may a say look at a 1000 watt digital ballast system with 1 dual arc bulb (one bulb with a 400mh and a 600hps).............this should get u 6 square feet of grow room 8 if u do not care about denceness

as for the hood system the cool tubes are the shit just go for the big hoods not just the wing add ons( personal exp i like the hood much better then the winged tube only)


for the venting math i need W x L x H of the room and then u devide that by 3 and that is the minal amount of air u should be moving every min
a 4x4x6 tent i need to run at 32 cfm ........i have 2 600watts in mine with a exhust fan of 400 cfms and a powered intake of 240 with passive open to make up the extra to avoid concaved walls
 
jjoe75

jjoe75

Active Member
I am in an unused bathroom that is 8' x 6' and am using a 1000 mh. I keep the door closed except for about 6 hrs at night and my room runs about 5 degrees warmer than the rest of the house with ventilation. My fan is undersized at 171 cfm but it was what I could afford ( put most into genetics, soil, nutes) my temps go from 75 at night and up to 83 during the day but I am in florida so we are still hitting 90 during the day. I would think you would be better off with some ventilation even if it is undersized. Make sure you pull the air across the lamp not blowing into it. Started with it the wrong way and was hitting 89-90 during the day and switching it to sucking air across it I shaved over 5 degrees of my temps. Filter-light-fan-exhaust.
 
justugh

justugh

Well-Known Member
jjoe75 said:
I am in an unused bathroom that is 8' x 6' and am using a 1000 mh. I keep the door closed except for about 6 hrs at night and my room runs about 5 degrees warmer than the rest of the house with ventilation. My fan is undersized at 171 cfm but it was what I could afford ( put most into genetics, soil, nutes) my temps go from 75 at night and up to 83 during the day but I am in florida so we are still hitting 90 during the day. I would think you would be better off with some ventilation even if it is undersized. Make sure you pull the air across the lamp not blowing into it. Started with it the wrong way and was hitting 89-90 during the day and switching it to sucking air across it I shaved over 5 degrees of my temps. Filter-light-fan-exhaust.
Click to expand...
i am guessing u are using the exhust fan that came with the bathroom man

if u have some skills with tools may i say go up into the attic remove the old fan system and replace it with just a simple 6 inch inline booster fan (240 cfms) ...........then just need a low intake hole in the door (a cat door)
 
jjoe75

jjoe75

Active Member
It is an inline I have, it is a 4" though and only 171 cfm. I have it venting through the old light fixture hole into the attic. I plan on upgrading to a 6 inch with at least 2x the cfm before the next crop starts. This is my first grow in this room so I wasnt sure of the temp level with a 1000 mh/hps but I figured I could keep it close to optimal with at least some air cooling from an inline even if it was too small.
 
jjoe75

jjoe75

Active Member
I cant alter the door or room in any way. The walls are tiled from floor to ceiling so the attic is the only option to exhaust
 
niggles8

niggles8

New Member
I have 9 plants vegging now. Im only expecting to get 2-5 females out of the batch.
This is a personal grow, I have no need for 8 or more plants and I do not intend to use
the whole 5x5 area within my 12x10x10 room. Would opening the door for 8 or so hours
a day help? I really don't want an exhaust coming out of my grow area. With that being said,
is it possible to use a 400w hps without exhaust? I'll use the MH bulb included and the
CFL's I already have to finish veg, and the HPS for flowering.
Thanks
 
JonnyAppleSeed420

JonnyAppleSeed420

New Member
One light in a big room will only require minimal ventilation. You always want to bring fresh air in for the girls anyways. If you have a tube or hood that is sealed and you exhaust it out of the room you will only need air for circulation JAS
 
ButchyBoy

ButchyBoy

Well-Known Member
niggles8

niggles8

New Member
no tent, just an unused bedroom.
I built a 5x5x5 wooden structure with shelves and places to hang light fixtures.
Like I said I don't care if I dont utilize all the space I have.
I would love to end up with 3-5 female plants, I'll take my time with them, topping and training
each to be thick and bushy. Id say after a foot and a half - two feet tall is when id start flowering.
I dont know much about yeilds per plant, im purely experimenting here. I haven't ordered a HPS
system yet though i was looking at that exact apollo light in 400w.
Im happy to hear some think I would be ok without an exhaust fan in the bedroom.
With the price difference being so minimal Id be open to consider the 600w but is that really
necessary? As said I dont know much about yeilds, but id be very happy with a dry QP.
Any thoughts?
 
niggles8

niggles8

New Member
Ive been using tin foil taped to cardboard boxes surrounding the small grow area since sprouting. Plants are just about 2 weeks old now.
Janky I know, but it does a little at least.
 
ThePerfectGrow

ThePerfectGrow

Member
niggles8 said:
Ive been using tin foil taped to cardboard boxes surrounding the small grow area since sprouting. Plants are just about 2 weeks old now.
Janky I know, but it does a little at least.
Click to expand...
Flat white paint would b better - Here's the chart of percentages of light reflected:


Foylon 94-95
Reflective Mylar 90-95
Panda > 90
Flat white paint 85-93
Semi-gloss white 75-80
Flat yellow 70-80
Aluminum Foil 70-75
Black < 10
 
ButchyBoy

ButchyBoy

Well-Known Member
Is your 5x5x5 enclosed or open to the room? if open to the room, the heat won't be a problem other than proximity to the light itself. the 600 can be run at 50%, 75% or 100% of its output so you can run it more like the 400 but have the ability to run it at 600 if you need to. Price is close to the same also.
 
greenlikemoney

greenlikemoney

Well-Known Member
Dude, do NOT use tinfoil, mkay.....and you will easily get a QP, but don't expect a QP per plant ( although that COULD happen )....as mentioned, if that 5x5 is not enclosed you should have no heat problems.
 
niggles8

niggles8

New Member
5x5 is open to the room. The structure I built is just supports and overhead beams.
No heat problems, does that go for both the 400 and 600w? About the tin foil,
are there any suitable, not so expensive replacements or would you recommend just
getting rid of it all together. A QP per plant would blow my mind Id be set for a while.
 
niggles8

niggles8

New Member
I also have a question about the ballast that comes with HPS systems. Im reading that
they get pretty hot. I was wondering where you guys keep yours, like what surface you
keep it on, do you mount it up high or keep it mounted closer to the light itself, let it sit on the floor?

Thanks again
 
ButchyBoy

ButchyBoy

Well-Known Member
For a cheap foil replacement head over to wally world. In the camping section is a emergency blanket made of mylar. They are cheap!!!

My ballast barely gets warm and is mounted to the wall in the flower room. As for the electrical use... They will add to your bill. How much do you pay per Kwh???
 
niggles8

niggles8

New Member
not sure about the $/Kwh ill get back with that. I have another cooling question.
I just purchased a HPS system with a cool tube. The one you shared in the link. There was no 600, just 400 and 1000w so I went ahead and got the 400. I think it will be adequate since I am willing to downsize my grow if necessary. Does this cooltube require a fan pulling air across the bulb constantly or can I get away without with earlier said measurements of the room and grow area?
 
ButchyBoy

ButchyBoy

Well-Known Member
They were out of the 600's ? Bummer, hope they get more real soooooon!!!!

You can run the tube without the fan but you need to pay attention to the heat. Hold your hand under the light palm down and feel the heat with the back of your hand. That heat will burn your plants if too close. With the fan on my 600, I can put my hand within an inch of the tube without getting burned. Without the fan is another story.

Edit: How many watt's are you running now with the cfl's?
 
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