How long does your CO2 levels last?

[riverrat]

I finally scraped up some change and invested in a CO2 sensor. set up a tank and started keeping my co2 levels at an average 1500 ppm. After thinking I have sealed the flower chamber well. My levels leak down fast and I'm running through lots of co2. To those of you that inject co2, at what rate does your ppm go down after your co2 valve closes? My leak rate seems to be about 50 ppm per minute.

Just how well does the room have to be sealed? my co2 valve cycles about every 7 minutes and stays on for about 40 seconds each time. How well does your room hold co2?

thanks
RR

 

[HUGE]

I have a10x12 area and using the fuzzy logic controller I go through a 20lb tank every 7 days.

 

[growshopfrank]

in an 8'x8'x20' shipping container packed with plants using a fuzzy controller maintaining 1000ppm 32 to 35 days out of a 20LB tank

why 1000 ppm? Well I experimented with concentrations from 5000ppm down and yield didn't drop till around 600ppm so I came up with 1000ppm as a productive safe amount

 

[dunkydunk]

I have an 8x9x7 room and a 20lb tank lasts 6-8 weeks at 1150 ppm.

All this is relative however. My room is completely sealed, and the ambient co2 levels are around 700ppm. The greater the difference between your set ppm and your ambient ppm, the faster you'll lose co2. If there are any leaks in your room, the rate of loss will increase accordingly.

There is also the unknown factor of how fast the plants are taking up the extra co2.

 

[riverrat]

Thanks for the replies, my flower room is small 2x7x7, and a 5lb tank (largest I had on hand) last me 3 days so at my leak rate it looks like I'ed go through a 20 lb tank in about 12 days. I might have to rethink the tank system and go with a co2 generator. It's a 50 mile round trip to get the tank filled, and it cost me $14.00 for 5 lbs so a 20 lb tank refill is gonna run $40.00 or so. Thats about $100.00 a month in co2 cost. I don't think it's worth it at that cost. My plants are loving it but unless I can find a cheeper method, they may have to do without.

RR

 

[odium33]

I have a10x12 area and using the fuzzy logic controller I go through a 20lb tank every 7 days.

same here, 7-9 days per tank, 10x12ish room, with a plywood boxed out AC, and untaped reflectors (most likely the largest leaks we have)

 

[foaf]

My 20 lb tank lasts about 2 weeks in a 3x4x10 space at 1500. The welding place near me quit filling while you wait, you would have to leave it and pick up after they did a batch, that's why I'm changing. I thought it was too small for a generator, but I find this "minigen" thing that's on its way in the mail. Its small, water cooled or not, and less than $300. It should be just right, and filling propane tanks should be much easier. In my case, I have natural gas there, so I might convert it if possible.

 

[compost]

My 8ft cubed room goes through a tank about every 14-17 days at 1500ppm. Riverrat when I am in my sealed room with the light ventilation on and the AC running and 2200 watts rocking my CO2 levels go up. Ive seen them go over 2300 when I am in there an hour straight. If you see huge drops in your CO2 levels your room is not sealed good enough.

My old room had a portable AC unit, no seals on the lights, and bad airflow and I would watch the CO2 levels drop 50-100ppm at times. Seal your lights better, seal your room more, increase air flow in your hood exhaust, and never use a portable AC unless it has 2 air ducts on it.

 

[riverrat]

My 20 lb tank lasts about 2 weeks in a 3x4x10 space at 1500. The welding place near me quit filling while you wait, you would have to leave it and pick up after they did a batch, that's why I'm changing. I thought it was too small for a generator, but I find this "minigen" thing that's on its way in the mail. Its small, water cooled or not, and less than $300. It should be just right, and filling propane tanks should be much easier. In my case, I have natural gas there, so I might convert it if possible.

Let me know how that MiniGen works out for you. I'm looking at that unit as well.I have a propane heater in the garage that backs up the tank system, and when it is on my co2 hovers around 1100 ppm or so but I wont be able to use it in the summer, and I hate to run that heater when I'm sleeping. I know I'll have to ditch the tank system, just too costly for my small grow. and I doubt I can get the room sealed much better. It seems co2 is a real bitch to contain.

RR