Red Knobby Sea Star Sick????

[SnoopyDaPimp]

So two days ago in the middle of the night one of my powerheads feel off the side of the tank and into the DSB. When I woke up at 630 am my tank looked like milk. I quickly retrieved the powerhead after turning off the power. 45 minutes later my kids were off to school and I was able to fix the tank once the sand had settled a little bit. I found my red knobby sea star under about an inch of sand. The first day he was but now he has not moved in nearly 24 hours. It ate today but will not move. Any suggestions or if anyone has had a similar problem please chime in.

My hermit crabs and platinum clowns are all looking healthy and having fun. I couldn't find anything through the search with someone that had a similar problem.

Fortunately, I never had an ammonia or nitrate spike. Tank info below with current data:

46g tank
4.6g refugium
salinity 1.025
ammonia 0
No3 0
No2 0
kh 240
ph 8.2

 

[Calappidae]

Could've had a nitrate spike when it was being stirred up perhaps. They cannot tolerate high nitrates.

Other than that I'd leave it be and see what happens.

Also just want to clearify..
Protoreaster linckii or Echinaster echinophorus species? (both commonly refered to as red knobby)

 

[SnoopyDaPimp]

Protoreaster linckii

He just stays in place and randomly lifts or lowers one or two arms.

I have been continually checking my nitrates and even when the water was still "milky" the nitrates still came up 0.