Squamosa question

[danny zubot]

My 5" squamosa clam hasn't fully opened up in about 3 weeks now. It sits at the bottom of my 24" high tank under 1 400 watt 14K bulb as ot has for the past year. I can't figure out why it won't open since nothing has really changed in the tank except the lack of a sandbed since I moved December 1st.

My levels should be ok with:
Ca @ > 400ppm usually
Alk @ 7-9 KH
Mg @ >1280ppm.
I do water changes with OP Pro salt every 2-3 weeks and only dose iodine other than what is needed to maintain the above levels.

The first time a noticed it not opening is when I started to use a two part appoxy for securing corals. But its been three weeks now! Another note, I medicated the tank for cyano about 4-5 weeks ago. I haven't been feeding the corals (phyto) as often as I have in the past, maybe once a week.
Any red flags going off regarding my practice?

Also, I know the clam is still alive because it did open half way (compared to normal) about 4 days ago.