Dick is right. Agree with everything Dick said.If in fact your NO3 is 1 and po4 is 0 you will have a hard time showing any growth. Corals need NO3 and po4 for nutrition. I personally would get the NO3 up to 5-10, and po4 up to .03 to .08. There is a big misconception that corals need very low NO3 and po4. There are numerous articles on reef2reef that stability, water flow and lighting is much more important.
Dick Flanagan