What surface temp are you getting at the canopy?

I'm having trouble keeping the temp under my 600w air cooled HPS down in a 4x4x6.5 grow tent (luckily theirs no girls in there yet). I've been told by a lot of people with similar setups that there temp is only about 74-76. My temps are staying between 72-74 along the tent wall , but If I put a thermo 18" directly under the light with its biggest surface facing the bulb it will get up to 84 and nothing I do seems to reduce that radiant heat. Is it possible that most people are taking there temps in less direct light, and if they really took a surface temp of something right under there light it would be hotter? So people with IR thermos out there, what temps do you get on the surface of your canopy directly under you light and what kind of light are you using (wattage, AC or not and at what distance). Thanks

This picture helps illustrates my point. The white thermo probe hanging down a few inches past the edge of the reflector is at 72F, while the surface temp of the tshirt facing the light is 81-84F using an infrared thermometer. If I put the white thermometer probe directly under the light it reads about the same as the tshirt
t.

Also, what is that max leaf surface temp you would want to see assuming the ambiant air temp is around 74-76 inside the grow tent?

i grow in a tent 2/1.5/3 meters with 2 600 watt hps and i get canopy temps at 74 to 78 and outside of the plants the tent walls are running 73 to 75. i have to have 2 tt200 vents bringuing air in fro outside as i have no hoods. i found that when i put one of my 5inch foil duct above a oc fan that was blowing air directly down the middle of the tent(from right to left) lenght ways at mid height to canopy height it brought my temps down to 74 to 78 from 82 to 86 also brought humidity down to 45 percent.

spitsbuds said:

i grow in a tent 2/1.5/3 meters with 2 600 watt hps and i get canopy temps at 74 to 78 and outside of the plants the tent walls are running 73 to 75. i have to have 2 tt200 vents bringuing air in fro outside as i have no hoods. i found that when i put one of my 5inch foil duct above a oc fan that was blowing air directly down the middle of the tent(from right to left) lenght ways at mid height to canopy height it brought my temps down to 74 to 78 from 82 to 86 also brought humidity down to 45 percent.

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Wow, that's really interesting. So maybe my problem is more about air flow inside the tent than the actual CFM I am cycling through. I'm a little confused on what you did though, are you saying you put one of your intake vents right behind your circulating fan so that it was blowing air across the room directly from the intake?

sorry for the delay. ye thats what i did and all my problems vanaished the other intake was brought in to at the bottom of the tent. so one above my oc fan pushing air through the middle and the other at surface levell. i was shocked myself ans this is no joke. whn the temps outside are freezing like now in the uk. the air i drag in is very cold and i hae to have a small oil radiator in the tent to keep the temps above 72. i thought about turning one of the intakes of. but the plants love the breeze plus the extra co2 . lol this is with 2 600 watt hps and no air cooled hoods and i have perfect conditions. play about with it and you will find a way. the plant on the left is 3 week into veg from out the tent