How to raise the humidity level

i have a hydroponic closet setup with plastic enclosure with
fresh air pumped in and circulated.
the humidity and coolness is a problem the mist cools the air 20 degrees.
i am working with an aeroponic system as my nursery and a hydro ponic as my main grow area
lights: 250wt high pressure sodium blub and a 1000wt hps bulb
the misting system has a 5 gallon reservoir
i started the seedlings with flourescent lights in a tray with rockwool then transplant them to clay rocks....in the aeroponic system...

my questions is; how to raise the humidity level??

to who answers this question : Does he have a mister? Or what other apparatus do you use?

I don't have a mister... but put a bucket or a dish of water somewhere in there and let it evaporate. Buy a humidifier so you can regulate!

Whats up dude,use a vicks cool mist vaporizor and allow afan to blow into the mist which not only raises humidity, but also mists ur plants,so fill it with either spring water or distilled water,it works within minutes,
regards,
SB