that helps IF your water supply is treated with old school Chlorine... today a lot of "city water" is treated with Chloramine which doesn't break down by exposure to oxygen (setting a bucket out overnight) like Chlorine does.
Try a bucket of water without the lid on it overnight and one with the lid over night, after the water has sat for a day exposed, cover it with a lid for several hours then take the lid off and smell the water, if there is a strong chlorine odor even after sitting out a day exposed you may have Chloramine, if it's Chlorine the odor will fade.
To be honest, I rarely set my water overnight, my water has Chloramine so I can't remove it and my plants have never had any problems, especially root problems and sometimes my res. temps are round 80 degrees F. I just don't think it's a big deal..