Control the temperature in grow room

Hi everyone,I have a 3 hp AC unit (28000 BTU).Like everybody here,I want my grow environment to be cooled when lights on(I also got air cool reflectors for 600s) and be cooler when lights are off ! (From wat I've read that the same temperature betwee day n night will cause hermie and stress the plants)
So which way can I use to control the ac unit ? Thermostat/timer or ?? My room is 4.2 x 4.75 x 3 meters,will set the temp for day is 25'C and night at 23'C.Good ventilation (with industrial line of exhausted fan)
Thanks for your help and have a nice day my friends

Where do you get the air that's going into the hoods on your blower line? Your not venting your AC are you?

Does your AC resume last setting after a power outage?

SnapsProvolone said:

Where do you get the air that's going into the hoods on your blower line? Your not venting your AC are you?

Does your AC resume last setting after a power outage?

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THANKS FOR YOUR ATTENTION !
Holes to bring the air are outside of room ( Im a newbie,I read books and info,if smt wrong please correct me,thanks !) so don't mess up the stable environment of the room ! 2 6" to cool 4 600hps
I don't understand "venting your ac" ?
Yes it does,it is the old generation.It can do dat and runs very well.3HP and my room is 71 cubic meter.The room temp is 29'Celcius,way too hot !!! But it cool so fast in around 10 minutes to my points with the strongest mode of that AC !

you don't want an ac to cool a room too quickly. A slow cool works better

I don't know where you got the idea that the same temps day and night cause hermi. Unless I misunderstand you.

just most people cool the room off at night to allow the rootzone to cool down some imo.

80f during day and 65f @ night is fine without co2 I have found.

Ok your not venting your AC (you are getting air from another room)

Use a line voltage thermostat. If you want use a contactor and put the thermostat on the relay/contactor coil and feed this loop off the timed lighting so it will shut off coil voltage with lights and when lights are on it will run on thermostat control. Two switches basically in series with contactor coil

joe macclennan said:

you don't want an ac to cool a room too quickly. A slow cool works better

I don't know where you got the idea that the same temps day and night cause hermi. Unless I misunderstand you.

just most people cool the room off at night to allow the rootzone to cool down some imo.

80f during day and 65f @ night is fine without co2 I have found.

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Im a newbie and the internet is the only source of informations.Thanks for your correct,they said that if the temp of "day and night" is the same,it will stress the plants.Because in the natural,night is alway colder than during the day
Anw,I will try to make it "slow cool" ! Bad bad ass for a newbie

A slow cool, as Joe said, is best and it removes more humidity. Getting too cool in dark can cause humidity issues.

SnapsProvolone said:

Ok your not venting your AC (you are getting air from another room)

Use a line voltage thermostat. If you want use a contactor and put the thermostat on the relay/contactor coil and feed this loop off the timed lighting so it will shut off coil voltage with lights and when lights are on it will run on thermostat control. Two switches basically in series with contactor coil

Click to expand...

Omg,Im not an electrical guy.But I will try to figure out more what u say.Can you give me a picture or a little bit of explaination ? Forgive me

Buy an environmental controller. Use high amperage relay to run AC off controllers cooling outlet. Plug controller into the lighting feed.

Thanks for your help,still searching and learning !!!