I am a beginner with a 45 gallon freshwater tank that currently has 6 south african cichlids (med/sm to medium), 2 plecostomus, and a school of small tetra. The tetra were the first fish we bought along with fancy guppies to help with cycling the tank. They are still around and living with the cichlids oddly enough. Over time, we slowly added the cichlids.
We started the tank around 5-6 weeks ago and finally did our first cleaning and water change last week. About 25-30% of the water was siphoned out from under the gravel. I also changed the carbon bag in our Aquaclear filter. After re-adding the necessary amount of tap water back in, I also added the instructed amount of primer and bacteria per approx gallon.
The nex day, I noticed the nitrate and nitrite levels were pretty high at around 10ppm (NO2) and 40ppm (NO3). Hardness is around 180ppm, carbonate at about 40ppm, and pH floating around 6.5 - 7.
In an attempt to lower the Nitrite and Nitrate levels after reading some information online, I did a 15-20% water change. This time around, I have not re-added any chemicals. Unfortunately, this did not help as the nitrite and nitrate levels are still high after 2 days.
Any help would be greatly appreciated. I'm just not certain which method would be best and would really hate to kill or harm the fish. Thanks!