Thank you, nitrates 0 phosphate 1.0 ppm before water change just did a 15 gallon water change, maybe 60 gal total volume 55 tank, fluval fx4 and just over a year old but believe it has cycled more than once and not sure I trust my test kits though, showed calcium just over 300 and kh of 5 right after water change? But all corals and fish are healthy. Did just add the fx4 after sun sun failed and lost regular blue channel on my Hydra 26