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By John W
Posts:  146
Joined:  Sun Oct 24, 2021 1:11 pm
Hello, there are plenty of similar topics, but I haven’t seen anything exactly like this.

I have a smaller 2x2 grow tent. I started monitoring the temperature and realized when I cool it with a fan out the top, I lose all my humidity, and the humidifier runs all day. So I was trying to figure out ways to lower the temperature a few degrees without losing the humidity.

My thought process is to make something similar to a water cooler CPU system for the light, as the light (mars hydro) produces the majority of the heat.

I am a machinist so am able to create a custom water block manifold for the light - applying thermal glue to ensure it transfers heat properly, then have a pump and cooling radiator / fan outside the tent.

Pump will run the water through the manifold, and hot water will cool off in the radiator outside the tent.

Hoping this might lower temperature 5 degrees F during the lights run time (from 85 to 80). Not sure if it would have any effect during lights out, even 1-2 degrees would be neat.

Open to other ideas, I am familiar with peltier cooling but not sure how that would work in a tent as I usually see this online with glass terrariums.

Thank you very kindly.
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By NightRaider
Posts:  418
Joined:  Mon Jun 07, 2021 4:01 am
Have you tried venting the top without running a fan? Hot air rises and all that, so it's possible you could see some heat reduction without blowing all your humidity out with it. I do that on a smaller scale with a 15 gallon terrarium, and I only lose a bit of humidity while it still drops several degrees. Don't know how different it may be being different materials though, but I think it'd be worth a try at least if you haven't already.
By John W
Posts:  146
Joined:  Sun Oct 24, 2021 1:11 pm
Yeah I am currently running it with an open top and just a fan inside circulating air - humidity goes up and down all day, and from experimenting, although it’s not just terrible.

With a closed top and fan circulating inside I will peak at 92 degrees during the day, pretty much never have to refill humidifier.

Open top with fan sucking air out, temperature peaks at 82-83 but humidifier goes on all day long - probably runs through about a gallon of water.

Open top with the fan just circulating air internally, temperature peaks at 84-86, humidifier probably takes 3 days to run through a gallon or so

I will also add on that the light by itself raises temperature up from 70-72 to 78 in about an hour, then slowly up from there
NightRaider liked this

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