Weekly water changes with gravel vac on my 60 and 20 long keep the fish happy and growing quickly. I check my canister filters every other week (big bio load in 60) and clean pads monthly. I think weekly water changes are like rainfall in their natural environment and it's my experience that this does not stress them out. My 40 breeder reef gets water change every two weeks bc I have no protein skimmer and the tanks doing great so far.
I have not done water changes in my aquariums in the last 7 years water changes by hand a thing of the past. I have invented a water control system for aquaiums that maintains pH and water hardness eliminates Ammonia, nitrite remain at 0 ppm and nitrate at 3 to 8 ppms aquariums remain clean and clear. This system allso controls my out side garden Koi pond. Here is a video of my 180 gallon aquarium maintained by this system and at the time this video was taken the water has not been changed by hand in 4 years and as you will see the breeding was great. www.youtube.com/watch?v=bMD3VaxsG9c
This system will adjust control and maintain pH and water hardness monitored with a TDS meter.