400 Watts HPS Heat Question.

Discussion in 'Growing Marijuana Indoors' started by SweeneyWeeney, Nov 26, 2014.

  1. #1 SweeneyWeeney, Nov 26, 2014
    Last edited by a moderator: Nov 29, 2014
    Going into this my biggest fear is spending more money than I need to, because my reason for doing this is to be a little lighter on my wallet in the longrun; However sooner than later is better. I could probably throw a million questions that I have, however I'd prefer to get actually get an answer rather than scaring everybody away with an overwhelming amount of questions.
     
    Question: How much heat will a 400watt HPS produce in a 3x2x5 Homemade growbox? too much for the plants?
     
    Details:
    • 3x2x5(LxDxH)
    • Avg house temp: mid 50's to mid 60's winter (dad doesn't believe in using the heater lmao) 
    • 2 intake, 2 exhaust fans both at 21-76 CFM/600-2000RPM(if anybody can explain those too it would clear some confusion too) lol
    • 1 internal 6 inch direct fan
    I don't know if any of those numbers matter just trying to be as detailed as possible just in case they are needed.
     
    Im thinking since the house is cold maybe the 400 watt will help keep it warm even though its a tiny area? any ideas or useful knowledge?

     
  2. Thats a small space, but at least you've got some height, I would definitely recommend a cool tube as it makes it much easier to manage heat and I think you would have some issues with a 400w without one. I would say give it a go with a 400w with cool tube though.

    With regards to fans etc, you shouldn't have your intake be equal to your outtake as you want some negative pressure in the room otherwise it will stink. Do you have a carbon filter? What I have is a exhaust fan and then passive intakes and I think they are fine, but if you do choose to have intake because of heat temperatures or whatever then your exhaust should be like 3x more powerful than your intake (not exact and worth checking this). But not worth having intake = exhaust so possible save on one of the intakes and get a cool tube and carbon filter. FYI CFM means cubic feet per minute and measures how much air the fans can circulate per minute. RPM is revs per minute and measures how powerful the motor of the fan is.

    I'm by no means a master but hopefully this clears some things up, I think it's worth having more of a read before purchasing though.

    Let me know if you have any other questions will do my best to help.

    Tam
     
  3. What are cool tubes? And where would they typically be placed? Mounted to the top since cool air sinks?

    And what are passive intakes? Just vents? Will having the intake and outtake at different levels lessen the lifetime of the fans?

    I mean I'm not too concerned about the smell because I'm growing it for medicinal uses and am registered to grow and everything. But if I do put a carbon filter will I have to match the amount of intake with the amount outtake the carbon filter is supplementing. That's the reason why I wasn't to into getting a carbon filter just to save the confusion.

    Thanks for clearing up things a little bud!



    Sent from my iPhone using Grasscity Forum
     
  4. "But if I do put a carbon filter will I have to match the amount of intake with the amount outtake the carbon filter is supplementing**?" -- sorry wrote in a hurry lol


    Sent from my iPhone using Grasscity Forum
     
  5. Cool-tubes are glass tubes that go around your light and usually have a reflector for directing your light down while the tube itself directs the heat out the ends of the tube and away from the plants usually placed in front of a passive vent, which like you thought is just your standard tent vents with no fans, your carbon filters are sold by diameter to match your fan and vent holes and depending on the vendor can be bought at diff filtering levels. Do a quick search on amazon or ebay for fan/carbon filter combos I just ordered a real nice ventec package for a great price I can shoot ya the link if ya need. With 2 vent fans running you should be able to manage the heat if not and your ballast is digital try kicking it down to 75% or 300 watts and if still to hot you can lower it down to 200 which should be fine if you have good wall reflection. I would be more worried about the girls you are gonna grow outgrowing your tent, I am vegging a 4 ft Darkstar at 45-50 days that after flowering will end up at around 7-8 ft  and be a good 4 ft in diameter. Hope this helps if ya need more just ask.....
    View attachment 1627466
    this is my DS.... :D
     

     
  6. So if I'm getting this right the cool tubes just direct some of the heat away from the plants, most conveniently to where you'd want a passive vent or outtake fan placed? MIght look into those, thanks bud! And yea if you could shoot that link it would be great! know any good deals on lights?
     
  7. Well said. May I add that you want a minimum of 2ppsi pressure differential, and a heavier than normal balance of CO2 as a result?


    Wind is higher pressure air moving to lower pressure points. A fan works by creating low pressure at the intake, compressing the air, so it moves to the lower pressure at exhaust. Compression equals heat, expansion equals cooling. This is why using a canned air duster, the can gets ice cold in seconds when being discharged.

    If you're creating lower pressure, your ppm of CO2 isn't as effective by measurement (think the difference between availability of O2 at sea level and in the Himalayas...the ppm of the O2 is the same, the volume of O2 available at altitude is what changed)

    Calculate by volume, instead, for better effect. Rather than a canister system, I use measured pieces of dry ice in water in quart milk jugs (well cleaned) with the tops cut off between each plant. Your total volume of dry ice should be .04% of the volume of the tent.

    This cools, supplements CO2, prevents it from being dragged out quite as quickly (it takes time to boil off into gas, instead of being introduced as gas), delivers the cold down low where it will keep your growth medium cooler than the air. Not everyone will appreciate this method, it's just how I do it and why. If you do decide to try it, your tent volume is 25 cubic feet, so your chunks of ice should be in the neighborhood of 14.4 cubic inches, plus or minus. A bit of excess isn't going to harm anything, so a typical block purchased at the grocery will more than handle it....should actually be good if you break it up into equal chunks and drop it in the water for 2-3 days, since as the water cools, the dry ice evaporates slower.

    Also, if you duct the INTAKE of your fan, and use it to suck air over the bulb, it'll take more of the heat away, cool the bulb better (extending lifespan), and create a situation in which overpressure from blowing in doesn't force bulb-heated air back into the tent, since any imbalance in pressure will push air INTO the hood, instead of pushing it out of it.


    Just a few little tricks you may or may not want to use.
     
  8. I actually really wanted to try the dry ice method after I was asking about it in another thread in which I posted. It really had me curious what growth increases you could expect with higher concentrations of CO2 in your environment. Only problem is I'd just have to wonder how much money that would cost to have to keep supplementing it with dry ice every so often.
     
    The directed intake method seems like it wouldn't work so well however with me, unless I have a change to how I am planning to build my grow box. I was planning on having the intake on the lower portion of the box, and passive vents on the top portion, would this forced pressure of low cold air push some of the hot air out the passive vents and/or the carbon fliter? Or should I change up my design altogether?
     
    Really insightful points, thanks man!
     
  9. #9 Indie-Kah, Nov 29, 2014
    Last edited by a moderator: Nov 29, 2014
    Pound of dry ice $4.23 at my grocery store. That's about 2 cycles worth.

    You want to PUSH air in? Bad idea, if you're not wanting to create more heat. The air motion will, of course, still move some of it, but compression MAKES heat. Ever touched the bottles of a construction air compressor? Usually about 20 degrees hotter than the surrounding air.

    People DO it...but why would you fight physics when you can make it help you?

    You can exhaust through top or bottom, doesn't really matter...but keep your plants out of the direct airstream of the fan. Even a 14" oscillating fan is producing 30 MPH winds in its cone...that's "wind advisory" winds...capable of knocking off tree branches, if sustained long enough (of course, that's if that much wind hits the whole branch...but still)
     
  10. I couldn't tell you, honestly, what level of difference oversupplimenting CO2 makes, so long as there's enough inert gasses and O2 to trigger "normal breathing". Might be absolutely none. My reasoning for doing it the way I do is as I said...lower pressure, even if PPM is "proper" the AMOUNT available isn't enough.

    Same reason you wear an air tank if jumping HALO or climbing really high mountains...you can survive the pressure fine, but you just can't get enough volume of O2 to work properly. No matter how you try you can't bring the volume of O2 you need in order to oxegenate your tissue through normal breathing.

    Since this is why you have "tree lines" on mountains (and it is...the evergreens up near a treeline will keep on growing happily in subzero weather, and treelines are generally nearly a thousand feet below summer snow line), I just figure common sense says that if you're deliberately creating low pressure situations, you should make certain the plants have the volume of CO2 available where they grow best.

    Like I said, could be WAY off...but it hasn't harmed anything.
     
  11.  
     
    So how could I make physics help me? I'm so confused on how the intake and passive vent situation is supposed to work... ahaha
     
  12. OK...instead of blowing air in....which makes your area higher pressure than the outside, compressing air (which makes it warmer), suck air out...across the bulb, if possible.

    Wind is air moving from high pressure to low pressure.
    Fans create low pressure on the intake side to suck air in, compress it with the blades, so it moves rapidly to the lower pressure on the exhaust side.

    The movement of the air will take some heat...but not as much as expansion of air does.

    So if you "suck" the air across the bulb, since it's moving from high pressure to low pressure, the air is expanding---cooling. It's also moving, removing what heat it retains. It's also taking air IN across the bulb, so instead of carrying MORE heat from the bulb into the tent air, it removes it. If using a closed hood system, think about it...blow air in, higher pressure, any leaks push air that's been heated by the bulb through those leaks and back into the tent. Suck it out, instead, air goes INTO the hood via those leaks...air that's not as hot as air that's been in contact with the bulb|

    Removing air..creating lower pressure inside the area than outside, causes the more pressurized air to force its way into the lower pressure area. As that air is forced in, it expands to fill the volume...so it cools. That way the air coming in through a passive intake is actually cooler than the air outside.

    Make sense?
     
  13. #13 Rumpleforeskin, Nov 29, 2014
    Last edited by a moderator: Nov 29, 2014
    Small spaces can be tricky to keep cool, but very possible. You need to remove the heat from the lamp before it builds up. I started indoor growing in a small space like you described via a wardrobe closet I bought at  Homedepot.
     
    Who ever said to get a cool-tube, is on point. A cool tube or an air cooled hood are a must. The cool-tube hood must be connected to a 6" or 8" inline fan (canfan brand type of fan). I would advise hooking the fan to a remote thermostat. Maintaining a constant temp will be a good start to a successful grow room. Make sure to have two 6" holes at the base of your grow space as your passive intake. If you plan on growing in this space and want results, you have to upgrade to proper ventilation. Not hard to do and won't cost an arm and a leg.
     
    The whole dry-ice CO2 thing is not sustainable and useless if you ventilate, but great for camping trips.
     
     
     
    $64 inline fan 6":
     
    [​IMG]
     
     
     
     
     
     $37 Cool-tube:
     
     [​IMG]
     
      
    $45 Remote thermostat:
     
    [​IMG]
     
  14. Sweeny..sorry bout the time it took to get back holidays and shit....right...lol ok heres a link to a 400 that you can use for your veg and flower,... http://www.ebay.com/itm/400-watt-400w-Dimmable-HPS-MH-Grow-Light-System-Set-Kit-/150656047425?_trksid=e17004.m185&_trkparms=algo%3DSIC.NPJS%26its%3DI%26itu%3DUA%26otn%3D6%26pmod%3D121119199404%26ps%3D63%26clkid%3D2287422568792510878&_qi=RTM759770   you get everything ya need with it but the timer and ya can pick that up at HD or lowes for 5-9 bux, nutrients depending on soil I would use either General organics for soil or General Hydroponics for hydro, forget Co2 at this point your small space will handle that for you, supplementing Co2 will only increase growing speed but will decrease bud growth but somethings ya gotta learn yourself, I personally wouldn't use it. if ya want links to the nutes holler back..
     
  15. BTW the link will show ya a good rep new 400 w/ everything for under 100
     
  16. Smokintime, that link takes you to a "bat-wing" style HID. Not meant for a confined space at all. You could not keep that style of lamp cool in a grow box (you could bake cookies), it is intended for an open space grow room. Cheap is not always good.
     
     Huh? CO2 enrichment  will increase yield
     
  17. Without an air cooled hood you could make all kinds of food in that can. I guarantee it would hit 150 at least with no airflow. Air cooled hoods are better than cooltubes but cooltubes are a little cheaper. You lose something like 5% of the light because of the glass in the tube being round. Not that big of a deal though, cooltubes generally take up less space so that's probably the right route for you.
     
  18. we have already talked about getting him a cool tube, which stiil in a confined space will generate heat, this allows him to run the 400 at 200 watts which could help with his cooling as long as he uses some decent fans and air-movement, I have run a 400 watt hps gull wing reflector in a 3X3X4 foot millard tent no fans at 200 watts with excellent results, as to the Co2 I have not only researched the chit out of it but have also used it for a short time, it pushes the plant to grow much faster than it should resulting in poor stalk, stem and branching width and less dense buds, if you are happy with it then I commend you, I am just going by the many yrs of experience I have of growing and hae learned the best wat to great plants is staying as close to what nature would give it as its had millennia to perfect its growing technique., Also I am not telling them not to try it just not to get there hopes up and to give them all the info not just the pros of one style... 
     
  19. #20 Rumpleforeskin, Nov 29, 2014
    Last edited by a moderator: Nov 29, 2014
    People use CO2 to increase yield, Not sure what you heard. And you gave him a link to a uncooled bat wing hood (big no-no).
     
     I run my atmosphere at 2000PPM (on the higher side of what most growers use) via Sentinel CHHC-1. If it made smaller bud/yields, no one would make the thousand dollar investment. Most commercial grows use real enrichment.
     
    [​IMG]
     
     
    One plant 72 days from clone to harvest under a single 400 watt HID:
     
    [​IMG]
     
    What CO2 and proper temps can do to bud size:
     
    [​IMG]
     
    No one needs smaller yields and high heat.
     

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