Yea I have a a carbon filter and inlineDo you have a fan exhausting hot air out the top?
Even if there still seedlingsWell your under lit but I assume that's a 250w LED since you said full spectrum.
If so I wouldn't worry about 85degrees f, its where you want to be.
Are the plants starting to smell already? If not the filter isn't necessary and you could increase airflow by using the fan disconnected from the filter for now with a little modification. Possible to snap a photo of the setup might help others give you some more advice. Good luck!Even if there still seedlings