Moving to a 3rd floor apartment in about a week Red Sea 200, i wonder how people do water changes in apartments lol.
I have about 20 feet of clear tubing, I attach it to a pump and pump the dirty water from tank to bathtub.
For new water, I have a 20 gallon brute on a wheely thing, and fill it with the RO then mix the salt, then pump to the tank.
Easiest way for me.