A rapid change of the ph can be very harming to your fishes health. I would definately try to keep both tanks as close as possible. Temperatures in nature will vary much more than ph, ergo rain storms etc., and not bother the fish to any noticable amount.
Eheim pimp #128, 55gal 13x20x48, Eheim Pro 2227, CO2 injected, into the filter breather tube,4x 55w Pcs , 12 hr light cycle (sunrise/sunset simulated), Milwaukee SMS 122, faulty bubble counter replaced with M3 bubble counter..... moderately Planted, Plantex CSM+B and ferts
To steal ideas from one person is plagiarism; to steal from many is research