Small dehumidifiers for grow tents

[Yukonbud]

I want to control the humidity in my 4x4x6.5' tent. I can do it in the light hours with ventilation due to the tent staying warm from lights plus 35% rh outside tent. But in dark periods, since my basement is pretty cool, it gets too cool inside the grow tent. So I bought a small Vivosun dehumidifier. Put it on last night and checked it at about 5hrs of 6 dark and the humidity was at 80%! A couple of tsp of water is all I got in the Vivosun unit. So I am sending it back. Can these small dehumidifiers actually pull the moisture out of a humid grow room at an acceptable rate? If so any recommendations? I would appreciate any advise, thanks!

 

[Ramsamsam38]

I was looking to buy the right dehumidifier for my 2x4 grow tent for flowering... The one i bought is weak and im going to return it too .Need something small and powerful. 🤔

 

[ellz]

Here are 5 that were reviewed on houseweather.org

https://houseweather.org/best-small-dehumidifier/

The editor's choice is under $35 online.

I personally use a Frigidaire 70 pint when I need it and it works great but it wasn't cheap and is way too big for your space. They do make a 30 pint that is around $200 that is really good but I don't know if you'd want to spend that. The cheaper ones shown on the website above mostly use peltier technology rather than an evap system so they use hardly any power. The down side is they don't work that great.

 

[Tersky]

so do you have an exhaust fan? I dont understand how your rh can be 35 out of the tent and over double inside since the exhaust fan should be resupplying the inside air with outside air. Should it be a little higher, yes, as you have plants and wet soil but over double means you have a ventilation issue. I have found in tent dehumidifiers have a marginal effect as the air that matters is the air outside the tent because this is where your air comes from.

 

[Yukonbud]

I have a ventilation fan going when the lights are on to control heat so that keeps the humidity down too. At night it does not come on as the lights are not heating up the space so thus the humidity rises. So last night I hooked up my other exhaust fan to the tent to take out the humidity. Both fans are hooked up to controllers, one for heat and one for humidity. It kept the humidity down. The temp in the tent dropped to 19deg C so I guess not too cold. I like the tent to be a little warmer but 19 is not so bad and the humidity is in check. I suspected those little dehumidifiers would not be up to the task. They should not advertise as such -ie- "perfect for 4x4 grow tent" (I've seen them advertised like this)

 

[Tersky]

You need to run the exhaust fan unless you have the tent open. Otherwise you will get high humidity, especially if you just watered your plants (had a power outage at night after watering that day and had condensation on my buds!!!). It doesnt need to be on full blast but the air exchange is important to control humidity. I feel ya with the advertised for grow tent thing. i had to learn the hard way and still have that damn thing in my closet somewhere!