Check out my CO2? Is it enough?

Im on my 11th day of growing. They dont seem to be growing fast enough so I have my Co2 hooked up with a 170cfm fan PULLING the Co2 through into my tent. Im letting it run for 2 hours.Then getting it off there.
400 watt hps with cool-tube
82F with the co2
75 without

buuuummmmmppp

buuuuummmmmppppp