NO3 high .... But then again. LAst time used to have a period of EX high NO3 in my 2 feet and my current 3 footer too. Dose AZNO3 for abt 2 weeks but my corals didnt like it, so i've stopped.
Continue 10% weekly change... Added a fuge... now better liao. Dont expect overnight or rather... over the weekend changes unless u r willing to do drastic measures...(Really drastic... Total change of water, clean sand clean rocks type..)
Takes some time la. Not surprising if it will take up to a month.
BUT>>> then again. My motto... As long as the stuff looks alright and healthy... then...