Super Small Anenome

I have a green BTA that over the past week has been very, very small. I have had it for about 5 months. It has not grown any but has never moved from its spot. It has always seemed content. It is hosting a maroon clown but the clown doesnt spend time with it anymore until night time. I have never target fed the anenome over the past 5 months and it has been fine. My water parameters are as follows:
Ammonia: 0
Nitrite: 0
Nitrate: 15ppm
pH: 8.4
Calcium: 480ppm
The pH is the only parameter that is different than normal. It is usually around 7.8 however it is 8.4 now, but we did the test in the late evening.

What could be wrong? Any inquiries would be great.

 

pics would help

lower your nitrates
8.4 is good
what type of lighting do you have and photo period

and remember a moving anemone is an unhappy anemone

 

Lighting: Nove Extreme Pro 6 48'' bulbs: 3 actinic and 3 10,000K
Lighting Period: 2 actinics on 10 hrs. 4 others on 8 hours.

Anenome has never moved from its spot since the first night i purchased it which was 5 months ago. It is 6 inches below surface of water.

 

it only started moving now

 

I has never moved and still hasnt moved from its original location. It is currently, not moving. It is just small. It does not look unhealthy or anything, just unusually small.

 

has it closed up and it looks like all the tentacles are about 1/8'' long

 

That is correct. That is how it looks.
However, the light has been off for about half an hour and the anenome is bigger.
Is it possible that it is recieving too much light and is thus happy being small? Or something along those lines?