I would suggest that you get some new test kits that give you a more accurate measure. Nitrite usually means that something in your tank is or has cycled. Nitrate at 40ppm usually fish are fine with that but some corals would not be too happy however you should be able to test for the lower levels. I recommend using Salifert test kits. Although not perfect they are probably the best that are readily available in the hobby. I have heard that angels are sensitive to O2 flucuations or more importantly lack of it in a system. A good skimmer will usually keep enough going through the water column. If you want to keep angels make sure you run a good skimmer 24/7.
|