jlk
Aquarium Advice Addict
Not odd. Your tank has been processing huge amounts of amm & nitrites. Carbonates (buffers) are needed to do this. They are being used up & your ph is dropping because there isn't a sufficient amount to keep your ph stable. Just indicates its time for a big water change. Do as close to 100% as you can manage. Make sure you temperature match & properly condition the new water. Then redose to 4ppm & we will see how things look tomorrow!