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Need help with high temp from HPS, please

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    Need help with high temp from HPS, please

    I currently have a 4X4 tent running with a 600w vented hood with a 6 inch inline fan running through it attached to a carbon filter. It's much like the example 600w hps set up on GWE.I have tried all suggestions with negative air pressure, keeping the room that the tent is in at a low temp (roughly 70-73 degrees) and dark with hot air venting out the window. I have two clip fans blowing air over the canopy and a tower fan set up to blow hot air from the light.

    My issue is my tent will sit around 85-87 degrees (around 50% RH) with the light on. Right now my plants are beginning stages of veg so I'm not in too much trouble. However, I would like to get my temp from the light lowered, so my plants can be a little closer. I've looked at other set ups an it doesn't seem that other people with 600w hps have to go to too extreme measures.

    Like I said I've tried re positioning fans, speeds on the inline fan, opened vents, and cooled the room that the tent its self is in. I had the light(s) on 24 hour (started with lower watt light) but yesterday switched to 18/6 to allow some time to cool. I am thinking about removing the tower fan and using more compact round fan (or two) with more power to blow upward at the light. Other than buying a small AC unit for it, I'm running out of ideas.

    thank you for reading and appreciate any help.

    Just reading through another grow journal, and was thinking about a smaller inline for an intake?


      Have you tried it without the carbon filter?
      2X4X6 Quictent
      1.5x3x5 Gorilla tent
      600w LED (80)
      1000w LED (180)
      2 X Viparspectra P-1000
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      6" battery/usb fans
      Mother Earth 70/30 coco/perlite
      GH trio with Calimagic
      Lung room humidifier
      3 and 5 gal plastic buckets Nebulas coco for autos nute schedule.
      ArmorSi, kelp when needed
      Running at pH 6.0

      Grow 3
      Northern Lights auto
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      Grow 4 8/23
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      If you can't run with the big dogs... stay on the porch and do bong hits.


      • WeedWithWillie
        WeedWithWillie commented
        Editing a comment
        Not yet. Considering it, although I may need it for flowering so it wouldn't be a permanent fix.

      I've tried a few different things today with no luck. I even tried adding a 4 inch inline for positive draw. Looks like maybe I have got to cool the room by a few degrees. Looks like I do need an AC for the room itself. IDK what else to do at this point.


        I’ve always had to use a air cooled reflector to grow under a HPS in a tent and I never used more than 400w. I prefer the ‘flow through’ type because the heat is trapped and your exhaust takes it right out. The reflectors are usually crap on these kind of hoods so I made a bigger one out of sheet metal. When I see pics of people growing under a HPS inside a tent without that type of hood I have no idea how they do it honestly. My tent would skyrocket north of 100 degrees in no time.

        Adding a link to the type of hood im referring to. If you have the kind of hood that just has a opening on the end to attach your exhaust to, I believe you’re realizing they don’t do much good at removing the heat.
        Last edited by bboyfromwayback; 07-14-2021, 02:04 AM.


        • WeedWithWillie
          WeedWithWillie commented
          Editing a comment
          I appreciate it. i have an air cooled hood that's similar to a lot of set ups I've seen, people say they work, but no luck with this. I have my 6 inch duct running through with my inline exhausting it out of the tent. idk what to do...

        • bboyfromwayback
          bboyfromwayback commented
          Editing a comment
          Right. As I stated, I’ve seen many pics of the same setup myself but IMO those hoods are useless. If you want to eliminate the heat get the type of hood I sent you.

        • WeedWithWillie
          WeedWithWillie commented
          Editing a comment
          Do I just hook my current ballast and bulb to this?

        I'm in a 5x5 tent running 1000 watt hps in a 6inch cool tube fixture the same as bboyfromwayback sent you a link too and there not expensive I paid $75. I run a 6 inch inline fan to exhaust the heat out side and I have a window air conditioner running full time I also change my light to come on at night as it's cooler at night I find this helps.


          I use a 600w HPS with an enclosed style reflector (not a cool tube just a glassed in reflector with an input and output on opposite sides of the light for the vent tubing) . I have the light vented directly out of the grow room which keeps it quite cool. If the smell is strong I hook up my filter to the other side of the light so the air comes down from near the ceiling through the filter, through the light and out of my grow room. I also set my schedule so the lights are not on during the hottest part of the day, which is also when electricity is most expensive so it is win/win.

          To be honest, if the room providing the air to your tent is cool and you are venting hot air out of the house I can’t think why your tent is hot. The only time my grow room gets hot enough to warrant A/C is summer but that is because my room is in my garage which isn’t insulated or heated/cooled. I grow outside in the summer so I don’t have to run the portable A/C. Not really sure what is keeping your tent hot.


            I appreciate the responses. I was able to get my temp down a little. I think my problem is just running this HPS in the middle of summer. My goal was to finish a couple grows with this light since i bought it a few years ago and haven't used it till this year. I am really considering LED specifically Spider Farmer. Like I said, I was able to bring the temp down a lil. Its less than ten degrees hotter than the room now, so I feel this is just a very common HPS issue.

            Also looking into the tube cooling hoods.


            • DeadlyFruit
              DeadlyFruit commented
              Editing a comment
              Where in the tent are you measuring the temp? The temp varies widely around the tent and may seem much hotter than the plants perceive it. Fans in your tent won’t make it any cooler overall but they will move around the air so it is more consistent throughout. When I want focused information on temp I will put a sensor in the plant canopy and be sure there is fan coverage so the heat is not congregating right under the lights. Ultimately it is the temp the plant is experiencing that matters and between fans and evaporation it isn’t always as hot as you expect under the lights. I reiterate that if the room the tent is in is cool, the tent well ventilated, the light enclosed and the air being exchanged regularly through the light and heat going outside I can’t see why the tent would be too hot. It may be summer outside but a room in an air conditioned house shouldn't change temp regardless of season. Also, 80-83 degrees when the lights are on (if I have my conversion right) is just a normal summer afternoon temp for plants growing outside and wouldn’t worry me much. They are less than temps on a hot day where I am in Canada.

              In short, if you are set on growing indoors during summer (I shift to outside in summer to save the environment from another A/C when the sun is the best grow light of all) I wouldn’t worry too much, the temps you are experiencing are not something that would worry me much.

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