Aging water with simple chlorine in it works well, but if you have chloramine in your water supply it's not so easy. Chloramine is much more stable and can take weeks to dissipate, although sunlight hastens the process (sunlight with also produce free floating algae). And if you do lots of water changes like I believe is needed, you would need vast amounts of water storage.
I have chloramine in my tap water and tested a closed container, the choramine had a 50% concentration after a week.
I use sodium or calcium thiosulfate to remove the chlorine molecule from chloramine. much faster, and not expensive, a 5 gal bucket of sodium thio dry salts last for years.
Below...
chloraminated water sample direct from the tap
By the way, the meter above is calibrated to test the amount of chlorine within the
chloramine molecule.
It is used to measure the amount of trace choramine, at the farthest of the water distribution system in my area.
You can easily test your own water with a swimming pool kit, if is sensitive enough and calibrated to measure chloramine at levels below 1.00ppm up to 4.00ppm.
Below photo a tap water sample after being treated with sodium thiosufate