I would say it's about cubic capacity regarding your airflow but mostly your exhausting maybe, is it possible for you to add an extra exhaust fan to your tent to help push the hot air out? And maybe an aircon for the loft to assist your tents intake temps?
can you start by measuring the temps outside the tent (over the course of a day) before trying to control those inside the tent? if your loft is too warm then you’re fighting a losing battle, because you have only got equipment that heats the air rather than cools actively.
if your loft is cool enough, then it should be a simple case of drawing more cool “loft” air into the tent when it gets too warm, that could be accomplished with an inkbird and a bathroom fan pushing air in through the bottom of the tent.
can you attach some pictures of your set up?
can you start by measuring the temps outside the tent (over the course of a day) before trying to control those inside the tent? if your loft is too warm then you’re fighting a losing battle, because you have only got equipment that heats the air rather than cools actively.
if your loft is cool enough, then it should be a simple case of drawing more cool “loft” air into the tent when it gets too warm, that could be accomplished with an inkbird and a bathroom fan pushing air in through the bottom of the tent.
can you attach some pictures of your set up?