I change 150 gallons every week in my 210. I match the tank temperature to within a degree or two. I have a hot and a cold pipe that come from a washer hook up i had installed so I just use the valves to adjust temp. This fills my sump which fills my tank and I dechlorinate directly in the tank. By the way I have a tankless water heater and they are incredible for water changes!

.. I always use warm/lukewarm water when refilling.