Recently someone posted a c02 calculator on this site. when i put in my info This is what I got / Grow room area: 792 cubic feet
Amount of CO2 required: 0.4752 cubic feet
On time: 1.00042105263158E-03 minutes

At this flow rate:
If you are using a 20 pound CO2 bottle with a regulator, it will last 6.13333333333333E-03 hours.
If you have a CO2 Generator a 5 gallon propane tank will last 1.89473684210526E-02 hours. My question is in regaurds to the on time mentioned above (this calculation was done to achieve 700 PPM )does this mean it takes 1 minute to fill up my grow room? Also the last 3 entrys for the above calculations tend to end like this E-03, E-02 and E-02 what does this mean? Thanks much this is going to be my first grow I have every thing else planned out pretty well this seems to be the last problem I need to address for now

It looks like you must have used a calculator that asked for your regulator's flow rate, usually in cubic feet/h (cfh) or sometimes Liters/min (lpm), rather than using a calculator to help you figure out dispersal time, use the one below to help you figure a good flow rate first.

The E-03 and E-02 is computerese for a number expressed in scientific notation. It is the same with most digital calculators too. Basically, it is a method of expressing very large or very small numbers, using base-10 exponents. One way we can write the number 100, is 10^2 or 10-squared. 1000= 10^3 (10-cubed), one million is 10^6 (10 to the power of 6), etc.

If I want to write out 918 billion, I could write, 918 x 10^9, but in scientific notation, it is merely convention to have only a single integer to the left of the decimal, so we can also write 9.18 x 10^11 (9.18 followed by 11 zeroes)

The same is for small numbers, but the exponent is negative. .001 can also be written 10^-3 or 10 to the minus third power. The number .000434 is written 4.34 x 10^-4 and that calculator you are using displays that in shorthand as 4.34E-4

So, 6.13333E-03 hours is also = .00613333 recurring or about .368 minutes or ~22 seconds.

Now that you know and (hopefully) understand, you can see that the calculator you used, the flow rate was set too high because it is saying that your tank will empty in 22 seconds at whatever rate you put in.

Try this calculator instead and you might find out that your flow rate should be set to based on how often you are going to recycle the air. http://www.hydrofarm.com/co2calc.php

Hydrofarm calculator is even worst...

I really meant to imply that both should be used in combination, one to get a value for the other to plug in.