Are you using tap/hose water to refill the tank?

I noticed this once when I did a water change. So here's what I do and the fish seem happy. I drain 50-60% of the water from the tank (130 gallon), do my pruning and cleaning like normal. When I refill the tank, I use regular hose water from outside. When the tank is at about 75% full I add 2 caps (20ml) of Auquasafe de-chlorinator and 2 caps (10ml) of Prime. Then continue to fill the tank slowy. When its topped off I add the remaining de-chlorinators & ferts etc. The fish are as happy as can be.

I have a PinPoint PH controller, which I used to use to control the CO2 but now its just running as a reference check to give a "general" idea of the PH. My PH will read as low as 5.99 during the day and go up to 6.4 at night, but after a water change the PH can be up towards 7.00-7.20 I run the CO2 on a timer now and not the PH controller, so after a water change it only takes a few hours for the PH to get back in line with the CO2 running full blast. (full blast is where I'm able to unject as much CO2 as possible without the fish complaining)

Anyway, it seems like by adding some water conditioner to the tap water during refill the fish remain calm and relaxed. When the tank is full you would never know I just did a water change, aside from the PH reading. The fish have no problem eating when I do an afternoon water change also. I have Discus eating from worm cups + Rams, Loaches, and other little fishes.

Lee
PS. I need to shoot some pictures of my tank and post them with a tank-bio/info, since I've been following the advice from Tom and others on there my tank has been flourishing. I have no algae, crystal clear water, O2 pearling, happy fish and I spend 1 day a week doing maintenance which takes 30-45 min.