Im not sure why everyone is so afraid of nitrates. Nitrates are not a big deal. Ive seen tanks that would freggin blow your minds, with colors that look photoshopped, and huge colonies, and that was with nitrate as high as 50. It is absolutely not needed to have nitrate and po4 at zero to have success. In fact, my tank looked far more pale/pastel in color when I did. Most tanks that have 0/0 are actually starving the corals and are doing more harm than good. My point is, you are far better off feeding more food to your fish (and indirectly to your corals) and having some nitrate/po4, than you are by starving them to maintain a 0/0 test. Once i realized this truth my tank went from near zero growth, and super pale colors to this:
And for what its worth, I had Zeo running when it looked like S*#T and when it looked good. The only difference? More fish, more food....
At this stage in this tank's life, I could see growth on my corals within 24 hours... no joke. It would drop about 1-1.5dkh per day of alk if not maintained.