Humidity too low?

Hello all, first grow here. i have 3 plants beginning 5th week of flowering today. Apartment complex is doing sprinkler system and fire alarm inspections this week so i built a 2x3x4 wood box to hide my plants. i slap a blanket over it and a TV on top and doesnt look suspicious at all. Anyways the temp is sitting around 84-86 when lights are on, 81 when lights are off. and the humidity is sitting between 21-29%. is this too low? most things ive read have a concern with humidity being to high. i have air intake on bottom. and filter/fan out on top. plus a small oscillating fan inside.
2 LED 100W
8 CFL 100W
They seem to be doing okay after they've spent a couple days in there. Any advice or info is appreciated thank you.

 

Awesome ty for your input

 

Sorry did not see an alert you replied. No i havent. I started my grow around 30%. put a bucket of water next to a fan a few weeks in because i was concerned it was too low, got it up to 40%. Moved to flowering box and now 6 weeks into flowering and still 20-30%. Everything looks great though. Buds are coming long nicely, trichomes forming. A little bit of leaf dying at the bottom, but this is normal mid-late flowering ive read. I think its important to have your fan blowing over the surface of the water to create humidity. This is how ive been doing so far. Picture is Day 72 from germination.

 

Finished off fine with no problems. First grow, very happy harvested a week early i think but it smokes fine Last image about 1/4 - 1/3 of what i had total. cant stop smoking it..