Problems with A/C and C02 in Grow Room

I've been lurking on the forum for awhile now. I used quite a bit of the information I found here to build my grow room. Since I found myself finding most the information I have needed on this forum, I decided to join. I'm hoping I can get some help with an issue I'm having from some of the experts here.

I'm having a problem using an A/C unit with my C02. Ever since I installed it, my C02 use has gone through the roof. I used 1/4 of a bottle in just one night. I'm going to work on getting some pictures posted later tonight.

For now I'll break down my grow room specs.

The room is 8' x 2.5' x 8'. For ventilation I have a 80 CFM fart fan on the bottom left side of the room blowing air into the room. I have also have a 4" diameter open vent on the lower right side. I have a 4" 160 CFM fan sucking air through a carbon filter that is currently acting as a scrubber, but I have ducting to vent it out of the room. The filter/fan is mounted high on the right side of the room. I have one wall mounted Ecoplus fan providing circulation. I'm using 1 - 600 watt HPS light in a 22" x 12" Super Sun 2 fixture. The fixture is cooled with a 4" 178 CFM fan that is drawing outside air from an air conditioned room and exhausting out into the attic.

With the above system, and venting the air out of the room with the carbon filter, I was experiencing temperatures reaching 89-91 degrees. However my C02 system was working perfectly, keeping the C02 levels where they needed to be without having to cycle much.

I didn't like the temps running so high so I put a 8,000 BTU portable A/C into the room. I am now able to control the temperature to perfection. I keep the room now about 74-76 degrees constant.

The problem I am having now is that the A/C is exhausting far more air than I expected. It's literally sucking the C02 right out of the room. There is a very slight vacuum now, not enough to hurt the fans or anything, but you can feel a very slight draft from the 4" open vent. I had to quit venting air out of the room with the carbon filter though, so now I'm just scrubbing the air with it.

My question is.. what options do I have to fix this? Should I put the A/C into the adjacent closet and have it simply blow cold air into the room? Or should I go with a larger vent, or add another fan to push air into the room..

I'm a total noob, I feel I'm getting the room close to perfection, but it's not there yet. I will post up some pics later that may help in giving me some advice.

Qwisty

I don't use CO2, so take my information for what it's worth...but I believe, if you're running around 1500ppm CO2, you want the temperatures to be right around 90 degrees Fahrenheit. Try turning the A/C off while the light is on, and just using it to cool down during lights off.

Wait for someone more experienced with CO2 to confirm or deny my statement before doing anything.

Welcome to RIU. Good luck with your grow.

Stoobie said:

I don't use CO2, so take my information for what it's worth...but I believe, if you're running around 1500ppm CO2, you want the temperatures to be right around 90 degrees Fahrenheit. Try turning the A/C off while the light is on, and just using it to cool down during lights off.

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I will admit, my babies seemed happier with the temps higher. Going to take some pics in a bit and load them up.

i have the same setup and the same problem but you can either have the temps higher which is good with co2 or you can use more co2. there are greenhouse controllers that will shut off the ac and exaust while the co2 is injecting and being absorbed and then turn on to exaust and so on but they are over $500 and you will still use the co2 faster. i am going to try moving the ac to the outside of the room and building a duct so it just blows cold air in. also my ac has a cap so you can just recirculate the air in the room so i may try that first. if you are using co2 you should have your room sealed off as well just fyi. hope this helps

i forgot to ask what kind of co2 controller you are using?

Here are some pics of my closet. I just turned the A/C off to see what happens. With the door open I'm getting about 80 degrees. Going to see what it does with the door shut for a bit.

queenster said:

i forgot to ask what kind of co2 controller you are using?

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Pics above show my set up. The room is pretty air tight. I'm using a basic controller, it just turns the C02 on or off when it reaches the set amount.

So far temps are only 83.5F