A couple things.
-I filter the air entering my tent. I use MERV13 across the intake duct (two fan setup, one for intake, one for exhaust). That may help keep your filter's intake & carbon cleaner and unclogged. Its cheap...20$ for enough to last you years while changing it out twice a year.
-Filters always damp-down the airflow...takes some work to pull air through that charcoal, therefore you have less air exiting your tent and the temps will be a little higher.
-I'd be more concerned at 73f than I'd be at 78f with lights on. I'm running ~675w of quantum boards and my 'lights on' comfy zone is 82-86f. I love to keep my lights out temps as close to that as possible, but in reality don't love seeing it drop below 77f. And I really don't want to see anything dip into the 60's.
-All of that is predicated on the fact that my LST (leaf surface temperature) measures at ~2.5f degrees below the ambient room temperature. So reading 77 means I'm really getting 74.5f. And 86f is really 83.5f. I don't really get any kind of worry until the tent hits 90...and then only if it does it for more than a single reading or two.
Running CO2 (beyond those mushroom bags which are more decoration than otherwise)...all bets are off, run up into those 90s