If you need help cooling your small space read this!

Ok, so let me tell you what I stumbled on to. Im sure im not the first but I cant believe the results. I have my small 5x5 closet space setup with two 400w HPS lamps. It has taken a lot of work to keep the temp in the room in the upper 80's with everything running. I watch the temperature very closely as I have seedlings that were about to go in there. I have been fine tuning the setup for almost 2 weeks straight. So, today I noticed my 14 gal reservoir was more than half empty. So I filled it up with RO water changed the PH to 5.8 and added my nutes. All day today the temp in the closet has been about 4-5 degrees cooler than usual. On average the room is consistently 8-10 degrees warmer than the temp of the air outside the closet. So let me get to the point. I added cold water today to the reservoir accidentally and it has cooled the room by a very noticeable 4-5 degrees. I didnt connect the cooling off of the closet with the cool water, like I said I accidentally let the water sit outside last night prior to using it. It only got down to 68 so we arent talking about cold water. The temp in my room was 79 and the temp in the grow closet was 84, I kept opening the door making sure both 400w lamps were on. Then it finally dawned on me, it was the cool 7 gallons of water I added when I woke up. Im in the process of making large frozen cubes of nute water to just drop in there daily.

Update I went to the store to buy an ice gel pack to keep the reservoir cold. The last like 3x longer than ice. But they didnt have any, so I bought 10lbs of dry ice at the grocery store. It is frozen CO2 right? So by adding a 1lb a day to the reservoir for cooling purposes It should also enrich the air with CO2 for the plants? That seems to make sense. The dry ice is 5x more effective at holding its temp over water, the gel packs are 3x more effective than water (but doesnt make your grow room look like a mad scientists laboratory). What do you think about the use of dry ice?

roots dont like cold water?also roots dont like c02 so dry ice in reservoir is a no no!!

thats a kik ass question when ya figure it out post it......thats interesting

Its a two stage reservoir. The bottom one only fills every few hours and only when its 2/3 empty. It really just the top reservoir that keeps a chill. I have an underwater thermometer in the first planter, its never been below 76 yet, but Im watching it and Im pretty sure the water can get in the upper 60's and plants should love it.




Pretty strange looking huh?

the colder the water the better

dude roots dont like cold your going to shock or stress your plants definetly not COOL

I'm pretty sure that dry ice dissolved in water will create carbonic acid, lowering your PH. You may want to watch closely.

nozthedon said:

dude roots dont like cold your going to shock or stress your plants definetly not COOL

Click to expand...

this is incorrect. the colder the water the better. the colder the water the more oxygen it holds and more nutrients it can transport

I read somewhere that that the plants roots like cold water in the 60's even. Im too lazy to track down the chapter in a grow book I have. Carbonic acid, I was just reading up on it on Wikipedia, It was saying that is has a tendancy to lower the PH but the carbonic acid itself is very unstable and doesnt persist. Im not claiming this as a fact but thats what I summarized from what I read. The PH in my RO water is about 8.2 and I have to constantly adjust it down to around 6. So this might be a good way to control the PH as well as releasing CO2 and cooling the grow area.

Update, I just checked the PH in the resevoir and its gone from 5.8 to 4.5 after about two lbs of dry ice in 14 gallons of water. I will bring the PH up but you were right about the carbonic acid lowering the PH, good call.

After thinking it over, its not practical even if it was good for the plants. 1lb dissolves in 10-15 mins. You cant plop a 10lb block into the reservoir it will billow towers of CO2 creating so much humidity it is going to cause problems, but it was an interesting idea. If you could figure out a way to control it and vent the CO2 properly it could be adapted.