Advice.. Ventalation

hey every1 im new to forums just thought id give it ago as seems theres alot of helpfull people on ere, so here goes this is my first propper grow in a GROW TENT. at the min i have a 1.2x1.2x2m tent ,600w sunmaster dualspec hps,not cooltubed.. a 5"inline duct fan for extracting , no intake at the min but in nxt few week. , should the intake i choose be bigger then the extractor like 6" or bigger or smaller then extractor?? just wondered bwt how long u guys extracted and intaked air to ur tents?? should intake ALWAYS be on ?? as i did do 1 plant in this tent before and temps was always high had to leave a door unzipped. an window open sumtimes, but as funny as it sounds it never had a smell to it really?? unless got real deep into buds with nose. got 3-4oz dry but it wasnt great ,HYDROPONIC CLAY PEBBLES, i know all my optimum temps an stuff just think i missing some more very basic information or mayby just worrying too much , so is it o.k to intake 24/7 / veg an flower, or shud i intake while extractor is on or off, ?? sorry if sound abit stupid but just wanna get everything spot on , as i know mostly all temps for stages of growth an stuff an strains but its just the balancing temps with humidity i cannot get the nack of!! so any tips an advice on hw long an how often u guys vent an stuff will be well appreciated... o an i havent got the £££ for enviro controllers an humidifyers an stuff ( I WISH LOL ) just seems so much harder managing an balancing things in a tent ,, so tips an info appreciated guys , thanx

Your gonna have to have em running 24/7 thats inline and blower, both, with an oscillating fan inside too. maybe you'll wanna get a controller to lower the speed of the inline fan just depends on what cfm fan you grab up.

How many cfm is your extractor? Sounds like it is too small, as intake sould be passive. What exactly type of a fan is it? Is it one like this or like this

The first type is not gonna cut it no matter what the cfm rating as they are more of a booster type that peeps use in their home heating and cooling duct work to help boost the air a bit over long stretches. The second is a proper extractor, and costs almost 10 times more then the first type.

You want negative pressure. Putting a intake fan in will give you positive pressure and with out a doubt raise temps, and the only reason to have an intake fan ever is if your temps are low.

this is my 5" extractor,an it says it does 280m3/h airflow rate on high an 220m3/h on low speed . so is this too small for this space would u say ?? an was thinking on getting the intake same model but 6" instead of 5"??? but shorly if i have them running 24/7 like paka child explains isnt that going to create low humidity?? how long an hw often do u have ur fans running for lights on an off, so i have to extract whilst the intake is on so that there is no pressure or high temps i thought a intake fan would cool the tent down .?? thanx for the help well appreciated..