Why does this happen?

[Smarkow]

One day it's fine. Next day, gone. Everyone else looks happy.

Params stable last few weeks:
Ca 465
Alk 11.7
Mg 1350
Ph 8.13.... can't get this to stabilize any higher
NO3 25.... I know.... Can't get it down but it's been this way
PO4 0.1.... actively trying to reduce

I have AP700s and T5’s over my tank. I’ve found that acros on frag racks near the glass with par 200ish seem to do worse than frags on racks at the bottom with 125-150 par. In my mind two possible explanations - not enough flow near the glass or par hotspots very close to the glass that a seneye can’t really measure.

Just my 0.02 :)