Acans closed up

[Bthomas]

Do acans sometimes close up for no reason or should I be worried? I have 4 different acans and they have all been closed up for the past 4-5 days. Here are the water parameters from 2 days ago.. I did a water change yesterday but have not retested. That was the first time I had seen nitrates test that high, they are usually in the 50 range. And I know Alk is low I've ordered some 2 part to start bringing it up but it's been low for awhile now.
Here are some photos of the acans as well (don't mind the aiptasia I'm working on it..)
Everything else in the tank seems to be doing fine

 

[Bayareareefer18]

Could be high po4 and no3 along with low alk