It is a Gig. Gigantea has pointed tentacles. Haddoni has blunted, round tentacles
Top of the column should have verucae and the foot should have pastel colors, green purple or blue.
Have you checked to see if the column has spots on it? IME when a gig has spots (verrucae) and it has a blue foot, the spots are typically harder to see.
Post a pic of the foot now while you have the opportunity. Only way to truly identify it.
If it was a haddoni then I have only seen young ones attach to rock outside of sand. You might not have a deep enough sand bed to keep it happy? Flow changes will also make haddoni move. I have that problem every time I clean my powerheads.
look like two Gigantea. However, the picture above is not ideal for ID. For carpet ID, the column pictures are most helpful, along with clear close up picture of tentacles and a over all clear picture of the anemone.
Use a stick to lifted the oral plate a little and snap a picture of the column please