African cichlids nitrite level control

Question
I recently started a 20 gallon tank. I have a aqua clear 5-20 gallon compasity filter system. I started the tanks cycle with a new product that was recommend by a employee at petsuper market called special blend. After the cycle I moved my African jewel cichlid that's just under 3 inches, 2 asorted African cichlids that are 2 inches and my albino bristlenose placo about 3.5 inches from my ten gallon. That same day I went and bought 7 1.5+ assorted African cichlids and a pictus catfish about 2 inches. Since that day three weeks ago Tuesday I fed them 3 times a day for about a minute. I tested the water and added the required amount of special blend recommend on the box. I did not change the water or clean the gravel these three weeks. On the beginning of the third week (last Tuesday)  I noticed my nitrates were through the roof. I did a gravel clean and water change that day. 25% of the water was removed and replaced with conditioned water. The next day I tested the water and the chemistry was still the same. I waited another day (today) and did a water change of 1/3 removed and replaced. A few hours later I'm still at the same levels I noticed Tuesday. Through these few past days I have also used a stabilizer called prime for the ammonia nitrates and nitrates. I am doing a lot of research today and I have read that a frequent water change for a few days a few times a day with rid the tank of these toxins. Is this true, recommended or is there another way to clear my problem and save my fish?

Answer
Cody,
Unfortunately, most large pet stores do not know much about the fish they sell. I would recommend not using the Special Blend. These products do not work and just adds chemicals to the water. The cycle process should be done without fish and takes 3 to 6 weeks to complete.  Your tank was not cycled before you added the fish. It is however, trying to go through it now. Keep a very close eye on the fish because this is the time in the cycle that can kill fish.  As for the fish, your tank is too small for the amount of fish and types of fish. You have overloaded the filter by adding 7 fish at one time. It is best to add smaller amounts to let the filter catch up, so to speak. The best way to get the nitrites down is by water changes. If they are very high then you will want to do a large water change of 50%. Test the water daily and if there are still nitrites, you will do a 25% water change everyday until the levels are back down to zero. I would recommend that you get a larger tank for the fish or you will continue to run into problems. Also, water changes are done weekly by removing 25% of the water replacing it with clean conditioned water.