Anyone knows whats wrong with my gonio?

[markred1123]

Gonio suddenly stopped extending out, my Alk, cal, mag has been constant all the way. Nitrate and PO4 is at 0. Dose 5ml of RedSea AB+ daily. Light intensity is at 75% LED maxspect recurve. All my SPS/ LPS started to retract their polyp too

Tank size - 20Gal/75L (AIO)
Alk - 10.5
Cal - 450
Mag - 1350
No3 - 0
PO4 - 0
Dose AB+ -6ml Daily

Might be nutrients overload or not enough?

See 1.5hr timelapse of my gonio:

 

[WIReefer]

I would say not enough asking for trouble with no3 and PO4 at 0. Also would drop Alk with your nutrients that low.

 

[markred1123]

Update, did a 90% water change, turns out that the water was soo dirty and full of brown algae.
Took a timelapse, the moment the water was changed.