GBTA Question

[walloutlet]

I've had this GBTA for some time now. Recently, its behavior has changed a bit from its normal nightly routine. I was hoping some other experienced reefers out there may be able to help.

My GBTA for the past few weeks, at night after the lights go out, tends to take the shape of a goblet or cup. It makes a cup and stretches way way out, I've never noticed this behavior in the past. Here is a crude picture of what it looks like.



The only thing that I can think of that has changed in the past little while is:
1. Changed Alkalinity mixtures from Kent's Coral Builder to Baking Soda
2. Added a peppermint shrimp, I have double and triple check against all known pictures on the Internet. I am positive it is a peppermint shrimp and not a camel back
3. Started dosing Calcium
4. Added another power head for more flow

During the day it also doesn't seem to expand as much as it used to, meaning the tentacles just don't seem as long.

One observation that I have witnessed is the peppermint shrimp seems to crawl over this anemone, since its dark I don't get a good view of what its doing but I doubt its trying to clean it. if you know what I mean.

Could this just be the anemone's self defence mechanism?

Could there just be too much flow and its holding on for dear life now?

Or, is this just normal behavior as the anemone has grown and matured a bit in my tank and I'm just an over zealous worry wart father?

Anybody else with a similar thing? Input is definitely welcome.

Thanks