I add Prime for the volume of the tank to the first bucket and then just add the rest of the water straight from the tap. I also adjust the water temp at the faucet to the tanks temp before refilling.
I add de-chlorinator just before I turn the hose on. filters are turned off only because the water levels are below the intake level. I add only for the new water volume, not for the whole tank volume. I usually change about 50% water at a time.
That's what I do with ALL my tanks FILLING 5 GALLON buckets all day for so many tanks is a chore for certain. I have a python water changer that can just fill straight into the tank but I'm scared the chlorine and other impurities will kill my fish before I add the dechlorinated treatment yeah the way I do it might seem like the harder way around things but I would rather be safe than sorry with all my fish I have I must tell you though that lifting five gallon buckets all day to refill water is a BACK BREAKER!!!