What brand of nutrients are you using?

Try to move your air in to a lower point, You will find cooler air closer to the ground then you would the roof line. Running lights in the night with cooler nights it also an option. Increase the size of your exhaust fan and move more air out faster that will help too.

Is your light hood air cooled? If not that is the one change you can make to bring the temp down quick.

Do you pre Ph your rock wool before you use it?

if your humidity gets to high you risk white powder mold so keep an eye out and make sure you have plenty of air movement around your plants.

How is your tap water? What is the starting PPM? Do you let it sit out to evaporate the chlorine for 24 hours before you use it?

What about supplements?

Do you use Cal Mag Plus if not you should it's a great supplement for Hydroponics and helps keep plants healthy. If you still have heat issues there are some products you can use to help plants deal with stress better.