I am a believer that pH stability in the system is far more important that NItrate levels and more important than having a set schedule for water changes. Almost eveything we discuss comes down to the long term effect on the pH and the aquariums buffering ability. Naturally, this is assuming the aquarium is already cycled and can handle the biological load.
That being said, I always suggest to newcomers that a weekly 20% water change is essential for success, but this recommendation is keep the buffering ability of the system at its maximum without using chemicals. I know that a newcomer is more likely to overfeed & less likely to recognize the early warning signs which let more experienced hobbyists know we need to increase our maintainance schedule.
Personally, for the average community tank, I change 20% biweekly on tanks with small fish and 25% - 50% weekly on tanks with big fish.
That being said, I always suggest to newcomers that a weekly 20% water change is essential for success, but this recommendation is keep the buffering ability of the system at its maximum without using chemicals. I know that a newcomer is more likely to overfeed & less likely to recognize the early warning signs which let more experienced hobbyists know we need to increase our maintainance schedule.
Personally, for the average community tank, I change 20% biweekly on tanks with small fish and 25% - 50% weekly on tanks with big fish.