To answer these questions there simply isn't enough info here. Can you put up a list of your equipment and your feeding routine? Lights What skimmer Refugium GFO Basically we need to know your nutrient import and export routine. What stands out at me is your PO4. Those API kits do not read low enough even if it says zero all tanks have some PO4. If it is showing something on the card at all most likely it is way too high. Also if not running a GFO reactor the first thing I would do tomorrow is buy one and some GFO.