Nitrite & nitrate levels

Question
My son has 2 tanks. A cichlid tank (29 g) and a smaller tank (10g) with neons and guramis. The tanks have been running for about 4 months. He has been doing frequent water changes (30%) and has always experienced high nitrate levels. Yesterday the water was cloudy and a number of fish died. We had the water tested today and the nitrites were very high as well as the nitrates. One store told him to continue to change the water and another place tells him not to change it for awhile. That this may be causing the nitrites to rise. Very flustrating. He fears for his cichlids (loves them!!)Our tap water seems to test fine. But after changing the water nitrates remain at blood red levels. Any advise?? PLEASE

Answer
Hello Josh,
I see you already tested your tap water. Good job!
OK,
Have you added anything different to the tank at all?
Sand? Rocks? Anything?
Cloudy water tells me that the tank may have started cycling again. Did you test the ammonia level?
PH level?
If all those are in safe range, then I would do 20% water changes on both tanks until the levels go down.
To be on the safe side, if you can get your hands on a product called Bio Spira, buy it for both tanks. It isn't cheap, but we are dealing with an emergency situation to save fish. It has to be refrigerated when you buy it and keep it cold till you use it.
One other thing...Did you change the filter or replace it with a new one?
Let me know.