Having trouble keeping humidity up when lights are on

[CrimNI]

Hi Everyone,

I have been having trouble keeping my humidity up when my t5 HO lights are on. I have a 4' six bulb fixture. The bulbs are arranged with three grow and three bloom. The bottom of the shelf is about three feet from the lights. The RH only gets to about 35% with the lights on and 50% with them off. I have one cool mist humidifier that is on almost all day. It is located to the bottom left of the enclosure. There is space for the humidifier to access the enclosure if it is completely closed off right above it. I'm using seedling trays as humidity trays that I got from Walmart, they are filled with water. The temperature can go up to 92 degrees if the enclosure's front is rolled down and about 82 if the front is rolled up. I have tried spraying down the entire thing to see how well that would work and the RH only goes up about 5% or so. I have a fan in the enclosure if needed but I'm not using it because it only brings the RH down, and the humidifier allows a little air flow. I haven't put any of my plants in it because I really wanted it to be perfect before putting them in this environment. I'm concerned that there is a problem with how I've set up my enclosure and if there is anything I should change. Should I invest in a better humidifier or get another one?
Attached are pictures of my setup and a fan that's located in the top left corner of the enclosure.