Cooling problems, advice please!!!

So I'm on my 2nd grow, last grow was my 1st and was a great success but I grew indoors last time and managed my temps easier! This grow I'm growing in same tent 2x4x5 but in a garage. Lights I'm using are 6 4ft t5 and my temps during lights on are hitting 88-90!! Too high, lights out holding 82 want them down abit more! So my setup I have I've created a port from a window behind tent and ran ducting from window to bottom of tent and ran more ducting out the other side on top of tent out another port outside! Cool air in at bottom hot air out as it rises from the top! Now Also mind you I'm not using inline fans, I purchased some inexpensive 6" circular desk fans and put one right into exhaust port blowing air into duct n outside and the other attached to window blowing fresh air from outside into duct n into tent! Is my problem fans aren't strong enough, temps outside are as hot as it is in my tent or is there a cheap solution I'm not thinking of? Recently took intake off added ac to window n taped a bag around vent cut hole in bag and attached ducting to bag! It cools it down but don't like the idea causing a lot of humidity and hard to control since thermostat isn't reading temps in tent it's reading temps in garage which are always 85+ therefore it won't shut off!! Any help or advice please help me out! Thanks in advance...

Ive been haveing similar problems due to the hot air, i think u started out right with a vent down low to let cool air in and one up high to let hot air out but instead of rigging fans up u need to bite the bullet and get some good inline fans, they have one at home depot its cheap but not alot of cfm, you need to get a good one like 6 or 700cfm, to expell all that hot air quick, and maybe one to blow air in, also if you have the money a mini split for ac if the inlines dont help, also air cooled hoods hook up to the exhaust vent, i got the portable ac from home depot the stand up kind and so far they suck, i mean it helps a little bit but as far as the electric to run it, its not very effiecient, i hope this helped, alot of people are haveing problems with this fucking heat, hope it end soon

You need to get a high velocity inline fan. The axial fan isnt doing much but blowing air around. It certainly isnt drawing air through the tent at any near optimal rate. You can lose the intake fan. Just get a proper exhaust fan and watch as it sucks the side of the tent in from the neg pressure.

You need a passive intake twice the size of your exhaust for the system to exchange air properly. If you have a 4" exhaust fan, you need 2 4" intakes, or an 8x8 or a similar area square.

If the outside temps are as hot as the tent then drawing that air in wont cool anything. You need to draw air from a cooler space. Basements, below grade concrete floors, AC'd home, etc