Nitrates were at the time of post 5ppm. To answer your question yes I did Carib Instant Aquarium Gravel-Tahitian Moon (Love the black look) and TSSWelcome to Fishlore 1*Risk!
By Nitr-5, do you mean nitrites or nitrates? Your profile indicates that you are aware of the nitrogen cycle and that you started your tank only a couple of weeks ago. Did you use anything to cycle the tank quickly, such as TSS or seeded gravel?
I'm assuming that you have 0 ammonia and 5 nitrite. What is your nitrate level? If my assumptions are true, then I'm thinking that your tank is still cycling. And, the pH will go all over the place while this is happening. These fluctuations can be stressful on fish.