i have 120 x 120 grow tent , my crop is 3 wk old and are 10 to 20" only prob iam having is temp , its ok leaving the door open around 75 , when i close door can reach 90 i have a fan putting co2 in , i havnt put a fan on my filter yet iam using 600w maxibright , whats a safe temp with co2 going in ?