bubble tip health. questionable??

[myles4miles]

I have a bubble tip that used to look really good, i have only had it for about a month and now it shrunk and during the early day and in the morning it kinda opens up to about 1/3 of what it used to look like or even less, but it opens up a bit a sometime during the day, and it hasn't lost any color, it also moves around its rock a bit, yesterday it was making a move for the back it looked like, now its back where it always stays at, but it's not opening that much anymore.

My thoughts on what could have done it are.
magnesium shift from 1200 to 1400( over the course of about 2 weeks)
anemone crab(porcelain crab) ???
I saw it touch a candy apple zoa (moved the zoa asap)
parameters
alk 7.7
magnesium at 1410
calc 400 something high side
nitrates are 10 maybe 20 using APi for nitrates only (so somewhere in that ballpark)
honestly, i haven't tested ph in a month but i have lots of hammers and torches and duncan zoas acros leathers and everything is doing perfect but the anenome.
salinity I try to keep at 35 ppt

any comments would be appreciated, ill post a pic of what it looked like 2-3 weeks ago vs now. but remember it still opens up like for a bit during the day i think, sometimes??

PS: THE LIGHTING DID CHANGE JUST USED AN ORANGE FILTER FOR ONE OF THE PICS!!

 

[Llyod276]

Hmmm, looks like the crab is the main culprit, how long ago was the crab introduced???
The magnesium, maybe.
People talk a LOT of smack about api test kits. Maybe take your water sample to an lfs and see if they can use a different measuring device...
If it only opens up that much and your crab sits square on it, the crab is blocking A lot of light.
How is the flow in your tank?

 

[myles4miles]

this is what it looks like this morning.
flow is good