Iām pretty sure the wilt youāre seeing in your plants is temperature relatedā¦ mainly in the rhizosphereā¦ meaning your plant has cold feet!
You said the temps range between 15C/59F - 23C/73F. Thatās on the cool side for the plant canopy, let alone the rootsā¦ I wouldnāt let it get below 20C/68F while growing Hempy style and thatās still on the cool side for the roots. Temps ranging between 23C/73F - 28C/82F would serve you better and your plants will grow faster when their roots stay warmer.
Since plants grow better when the roots have the appropriate warmth, your goal is to make sure the air temperature in the bucket zone doesnāt get below 20C/68F. Cold roots = stunted growth and can also cause nutrient deficiencies. Root temperature in soil isnt quite as problematic as it can be in any hydro application, like growing Hempy style.
Soil holds heat, perlite/vermiculite/croutons do not.
Also, I disagree that chlorine/chloramine used to treat municipal water is bad for plants.
What are the plants in your yard watered with, and how are they doing? Is it killing them? Probably notā¦ theyāre probably growing/living just fine with city waterā¦ even with the elevated pH (normally over 7.5 pH) the water company uses to prolong the life of the pipes in their district. My tap water comes out at an amazing 8.1 pH and I give it to all my plants straight from the tap. Iāve never experienced problems in doing so.
I do agree that chloramine is harder to get out of the water than chlorine is and setting water out for a few days isnāt enough time to dissipate the chlorine that is found in it.
If you had 10 gallons/37.85 liters of water with a chlorine concentration of 2ppm, it would take roughly 110 hours to fully dissipate, undisturbed. Thatās almost five full days you would have to wait until you can water your plants with chlorine-free water.
If the same amount of water had a chloramine concentration of 1ppm, it would take roughly 170 hours to fully dissipate.
If you want it to dissipate faster, then youāll have to boil it out or use a filter.