Led basement grow tent help (humidity levels)

Hello everyone , im new to indoor growing and have been at this for several weeks trying to get the right environment dialed in to start sprouting my fem. seeds.
I have a 2x4x5 growneer tent, elevated on a pc of 3/8plywood and 3/4 foil insulation overtop located on my cool basement floor. I have a 1000w sunraise LED light with a veg and bloom setting haging at 40" above the floor set on a timer for 18/6. I currently bought a 203cfm 4" inline fan with a charcol filter and have it set to its lowest setting on the controller running constantly (both inside the tent and 12 ft of vent outside the tent, attached to a "y"at the dryer and vent thru the wall). Im using a heater fan in front of my passive intake wich is keeping my temps where i want them at 25°c. (Can switch it higher or lower if any of you dissagree with that temp). I have a 6" s bend passive intake opposite my exhaust fan. Im using a tower fan set on oscilating and on its lowest setting 1 of 3. My hydrometer is locates in the side pouch, halfway up the tent. Im also using a ultras sonic cool mist humidifier to raise my humidity in the tent wich is located beside the tower fan and opposite the passive intake and opposite the charcol filter.(I put warm water inside thie resevoir) I cannot get my humidity higher then 30 32 % and replacing the water in my humidifiwr on the highest setting every 6hrs. How can i get it up to about 50 60 %?
I have acheived this before by simply putting the exhaust fan on a timer, to come on once an hr for 1 minute as anymore then that sucks to much humidity out. Ive changed back to running the exhaust alll the time because ive read that if you do not run it all the time, weed stench will flow back out the tent and into the room and I also read that air should be recirculated a certain amount (some say 3 to 5 times a minute, others 6 times an hr and im just confused with that since my 2x4x5 tent is only 40cfm , so technicaly my fan should 5 times that right)
To raise humidity in my tent,
Ive tried towels hanging but they dry out to fast. Ive tried a bowl in front of intake and i front of fan and does nothing. Ive tried a bowl with a towel hanging over the edge with water in it and doesnt do much neither.
After all my blabbering to get you guys the clearesr picture of my set up, how can i get my humidity levels up to 50 60% ?
Any info would be greatly appreciated, oh and i currently do not have any plants in the tent until i get the tent environment dialed in.
Thanks in advance to all of you and taking the time to read and come up with a solution. Cheers

I had the same issue

I use to run around 20% RH. Some times even lower.

I have my exhaust fan set on a temperature control. Comes on at 80F off at 78F. (Inkbird controler)

But I also have a inline duct booster inline with the high cfm inline fan. This booster fan runs constantly. So you alway have a bit of air exchange happening. But the humidifier can catch up. (Important at lights off,as the temp controller will never turn on the big fan) with out that you get humidity spike at lights off.

With that all going. I run a humidifier rated for a 500sq/ft. Has a 1.6gal tank. Hold 50%RH for 48 hrs on one tank full.