The main concern when acclimating new fish are pH, temp and salinity. A common practice among fish sellers is to maintain a lower SG
towards the 1.018 area. This can somewhat help the fish with bacterial issues and saves them on salt. The problem on your end is that if you have a higher salinity (which should be the case), the fish cannot easily adjust to increases in salinity all that quickly. Ideally, what you want to do is introduce the fish to a cycled QT
that can be matched to the transport water, ie salinity/pH. The temp is easily compensated by floating the bag before opening for 10-15 min. This means much less acclimation time and an easier transition for the fish.
Once the 4 week QT
time has passed and barring any treatments that may be needed, you can then do daily water changes using the main displays water at a rate of 15-20% each day. This will allow the new fish to gradually adjust to the mains water chem, the water changes on the main won't hurt either.