Hi! I'm new to fish keeping and I am struggling with my WP. I've read many articles and have learned a lot in the last 2 months. I cycled a new 75-gallon tank for 16 days, and WPs looked good, so I added 13 smaller African Cichlids. I've had them in the tank for 3 weeks now. In the last two weeks, my levels have gone crazy. The past 7 days I have done two 50% water changes and dosed with prime and stability each water change. My levels are Ammonia 0, Nitrite 5ppm, Nitrate 80ppm. The Nitrites will not drop. We have an FX4 and a sponge filter in the tank. Should I be doing daily water changes? Or should i stop with water changes and dose prime and stability? Any suggestions would help. Thank you!