moving altums

I have previously written about trying to move all of my altums ,or even all of the best ones into one tank.They (16) are spread over two tanks.
I have found that moving them is filled with peril. I have moved them gently without leaving the water.I have comingled the water in the two tanks. PH /TDS is as near to the same as I can get at 100 and 6. Any fish that I have moved goes off eating and even gets a little ragged. They begin that coughing spasm that they can do if irritated. With a temperature change up,feeding their favorite foods and being patient they come around after to a great extent after 3-4 days and and are about fine again after a week or so. During this time they are with other altums which are perfectly fine. Also,When I comingled the tank water,some of the fish in the tank that where I had removed some individuals,and some stayed put went off food for a bit.
I still have 5 to move and I want to move some smaller ones back into the original tank.I don't want to "sweat" out another 5 moves like this .Any advice? I am thinking to lower the ph in general to help them with the change. BTW ,when they get a bit ragged in the fins they do not get heals up very fast and perfectly.
regards Al

Re: moving altums

I went ahead and moved some smaller ones back into the original tank (where I have to move the big ones out of.)from the slightly higher ph 120 gal tank. So, I moved them from a ph of 6 to a ph below 6 ( but not properly determined as ph measurement is pretty crude by test kit)..that is to say : from bright yellow to medium orange by the API wide range test kit . It was quite disruptive to catch them and all got scared and I was a little nervous. All fish, both moved and those still in their original tanks, were perfectly fine in 5 minutes.
I had heard this before :You can evidently move them down ph but not up ph..
MIght be useful to know..if it is actually true