CO2 Logistics (will it work in this room, will it last?)

Upon reconsideration, I may be able to run CO2 but there are some things I can't seem to figure out. (Will the room maintain a reasonable grow environment, and will a tank last me a decent amount of time?)

I've only found one place near by that does CO2 refills at $2.60USD ($3.50CDN) per pound! (so like 60USD / 80CDN for a 20lb tank refill). - Now I see people saying a tank lasts 3 days, others say a tank lasts 40 days... If I can get 2-3 weeks on a tank, then it makes sense. But $60USD every 3 days would be crazy!

If I have a sealed room slightly smaller than (7ft. x 7ft. x 8ft. tall). Carbon Filter + Fan recirculating within the room. 13,000 BTU portable A/c. 1.6K W Led (Which will probably have to be dimmed).
->Do you think I will be able to maintain a reasonable environment?
->And how long can I expect a tank to last in this kind of environment (if magically everything is perfect, with a regulator and a co2 controller and everything is to the T.) I know no one can answer for sure, but if we can speak theoretically, what can I expect... closer to 2-3 days, closer to 2-3 weeks?

Currently in a similar area, in a 4x8 tent (which has a similar area to that of the slightly smaller than 7x7 room) I can maintain 75F (24C) & 50RH at full flower. It has a 8" extractor fan and three 6" passive intakes and a dehumidifier.

If your room is well sealed and you can maintain proper temps/humidity then you should get a lot of mileage out of a 20lb tank. It doesn't take a lot to double the ppm from ambient. A candle burning in a 4x4 tent will get it up over 1000 in 10 min if the exhaust doesn't kick in.

For general growing keeping it around 800ppm should give the plants a great boost without having to go full out on temps and everything else. I like to raise the ppm to 1500 and go heavy on feed, temps and light during the stretch then dial it back after. They just burst forth with lots of growth like that.

I haven't got my room sealed up yet so don't do a lot of it but hopefully will get the portable A/C etc to do it up right in a bit.

In a 10x12x7 with a 14k dual hose I went through a 20lb tank every 5 days running 1500ppm. Same set up with an 18k mini split it lasted 3 weeks.

Well, I might be stupidly assuming my room is completely sealed. However it is a solid concrete block (all 4 sides, roof and floor), with one exterior door (like the type of door you have on the Outside of a house). Insulated and everything. So I'm guessing it is safe to assume it is? (minus the one 6" exhaust hole which could be resealed.)

I just don't think it will be enough for a regular ventilation system - which is why I am now highly considering CO2 if I can make sense of it!

Currently only have a single hose ac, which I know will suck out CO2. So I will probably have to get a small mini-split. (ahh further down the rabbit hole we go lol).

@Pmbreno wow thats quite the difference! Knowing that I won't even look at a dual hose ac then!

On a note with cooling and investing in equipment, take into consideration your year round climate and design it for both extremes. I mentioned mini splits but I have since moved to water cooling to take advantage of the freezing winters we have that would afford me “free” cooling up to 5 months a year. You can get mini splits that operate down to -40 deg but are pricey and usually involve having to bring in an Hvac guy to your op at some point. Just something to think about. Maybe save you some money in the end. I have a few grand worth of cooling equipment out in the shop from the learning and growing phase of this ol rabbit hole

Pmbreno said:

On a note with cooling and investing in equipment, take into consideration your year round climate and design it for both extremes. I mentioned mini splits but I have since moved to water cooling to take advantage of the freezing winters we have that would afford me “free” cooling up to 5 months a year. You can get mini splits that operate down to -40 deg but are pricey and usually involve having to bring in an Hvac guy to your op at some point. Just something to think about. Maybe save you some money in the end. I have a few grand worth of cooling equipment out in the shop from the learning and growing phase of this ol rabbit hole

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I know this thread is old, but how does one water cool the room? Do you mean just the HID lighting, with an "ice box" style deal? I duno how you'd do it with leds or considering the drivers, etc.

They make air handlers that the chilled water runs through. Same concept as a mini split ac just using water instead of refrigerant

Oh. Cool. I'll have to learn a little about that. It's not a big "central air" style deal, is it?

2com said:

Oh. Cool. I'll have to learn a little about that. It's not a big "central air" style deal, is it?

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The outside unit looks exactly like an a/c condenser, the air handlers come in many forms. Up on wall like mini split, hanging style like a modine garage heater, ceiling mount with squirell cage fans, smaller units that can go on the end of an in-line fan. They also have central air styles as well. Good place to look at options would be Chillx

Pmbreno said:

The outside unit looks exactly like an a/c condenser, the air handlers come in many forms. Up on wall like mini split, hanging style like a modine garage heater, ceiling mount with squirell cage fans, smaller units that can go on the end of an in-line fan. They also have central air styles as well. Good place to look at options would be Chillx

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Too expensive and overkill sized units for me it looks like, but cool stuff and maybe there are smaller versions somewhere.
Thanks.