First off most are not aware of the correct way to read temperature and seem to place thermometers in enough direct or indirect light to cause a false heating of the probe. Heat is radiation conduction and convection and you want to read just one and omit the other two which in a hper reflective tent isnt easy.
You cant cool a tent the inline will merely suck the cold air out within a few seconds, you have to control the room the tent is in.
Im uk and not too hot to run during the day but i run at night just to avoid any daytime heat. Really my room temps can be higher in winter and more constant from the central heating - easily 25c before turning on the hps somedays, plants love it drink more grow faster.