Depends. If you are keeping live corals and inverts in a reef setup, I wouldn't use anything but RO
water...no need for Amquel as the resins strip chloramines.
If it is for a fish only tank, then I would use tap water with Amquel Plus for water changes. I personally prefer Prime, not for any specific reason though. My tap water is pretty good in my area, and being my tank is an FOWLR
(Fish only with live rock) I take a 5 gallon bucket, add salt, fill the bucket with tap water, then add twice the recommended dosage of Prime (=2 drops per gallon), and mix for one hour with a power head.
Modern salts mix into water very fast. Some tend to age water overnight to stabilize parameters, but being that I don't keep sensitive corals anymore, an hour of circulating seems to work fine for my needs.