sealed rooms are good to control escaping odor and to prevent bugs.
I'm in the UK. My tap water isn't so bad really. Most people that comes from other areas in England always say my local tap water tastes really nice compared to theirs. Currently mixing up nutes with straight tap water, canna coco a & b at 700ppm. I get ph 5.8-5.9 and I'm in coco. I'm happy with my tap water. I don't even give it time for the chlorine and other shit to evaporate. Filling the pot again and getting fuck loads of run off is more important.
You guys and girls in the USA are totally obsessed with reverse osmosis, air conditioners, humidifiers, dehumidifiers and all that bollocks. I just open the windows man. lol
I find it necessary to control humidity in my location, where it is so bad in the summertime that you sweat profusely 2 minutes after drying off from your shower; ie Kansas City, Missouri, United States.
The common saying in summertime is, "it's not the heat, it's the humidity".
The polar opposite happens in the winter. 30-35% RH is commonplace around the clock--so dry that your cuticles develop enormous cracks.
Also, temps can drop 30 degrees within an hour--hardly ideal for a weed plant in any grow phase.
Not saying marijuana plants wouldn't survive these conditions without a sealed grow area or tent; they do every season outdoors. However, imo they would be stressed out, lower yielding, lower potency, and possibly hermaphroditic if grown indoors under artificial light where I live.
That's why I choose to use grow tents. Not to mention they help contain precious artificial light to desired footprint.