slapper said:The process of nitrification produces acid which will lower your ph. The problem with doing a massive water change for you is that it will drastically alter your ph. I would recomend doing about a 20% change daily for a week. The next week do 40% daily.The third week get in the habbit of changing 50% every 3 or 4 days. You could probablly get bye with a massive water change once a week if you buffer the water with each change. You need to keep the nitrates low while maintaining a stable ph.
Most fish can easily overcome the fluctuation in PH.