here is a link hope it helps you
http://www.hydroponics.net/learn/co2_calculator.asp
a for your question Yes you can run it 2 weeks in
95 degrees is pretty extreme
85 - 90 is pretty good
Here is an easy example of how you can calculate your flow meter settings and the time to let it flow without using the flow chart above.
First Id like to point out that flow meters usually work in the units of cubic feet per hour and the length of time well be letting the gas flow would be in units of minutes. The examples below will take into account the conversions necessary.
Lets say you had a grow room that was 350 cubic feet in volume and you wanted to add 2000 PPM of CO2 to that space. Youll want to use a digital timer to open and close the solenoid for automatic injection so well be forcing the flow meter setting to allow for an exact number of minutes to flow.
The first thing youll want to do is find the flow meter setting necessary to add 2000 PPM in 1 minute.
Solution: Multiply the volume of your room by 0.12.
Example: 350 × 0.12 = 42
You would then set your flow meter for 42 cubic feet per hour and let it flow for 1 minute.
Now, that number 42 is what I call the magic number. Once you have that number all other calculations can be made by using it to divide from. The magic number incorporates the volume of your room, and the amount you want to add, so if you dont change the rooms volume and you always want to add the same amount, that number will be your magic number for life.
Most flow meters do not have a setting as high as 42 cubic feet per hour, so lets use the magic number to make more calculations.
If the highest setting you had on your flow meter was 15 cubic feet per hour youd need to let the gas flow for more than just 1 minute.
Lets find the length of time youd want the gas to flow using a setting of 15 cubic feet per hour.
42 ÷ 15 = 2.8
So, if you had the flow meter set for your highest setting of 15 cubic feet per hour youd want to let the gas flow for 2.8 minutes.
Now, we want to use our digital timer, so well need to change the flow meter setting to something other than the highest setting to let the gas flow for a certain exact number of minutes. So, we increment the 2.8 minutes up to the next exact number of minutes, which is of course, is 3 minutes.
Now, we just use the magic number real quick to find the flow meter setting necessary for a 3 minute injection.
42 ÷ 3 = 14
So, if the highest setting you had on your flow meter was 15 cubic feet per hour, you wanted the flow of gas to happen in an exact number of minutes, your grow room is 350 cubic feet in volume and you wanted to add 2000 PPM of CO2 to your grow space, then you would set the flow meter for 14 cubic feet per hour and let the gas flow for 3 minutes.
See, the magic number can be used to find either the flow meter setting or the time in minutes to let the gas flow just by dividing what you know (from the magic number) to find what you dont know. Whether youre dividing by the time, or the flow meter setting, youll always get the answer youre looking for in the proper units.