Welcome to the board
First of all I don't understand your lighting, do you have 2 seperate systems going for lighting? All VHO?
2nd, thats not enough lighting for an anemone, you will need to reach the 4+ watts per gallon in order to have one survive. Please remember these are a photosynthetic animal and must have light to survive or it will be a downhill spiral to death for it. Feeding can help but is no long term substitute IMO, IME.
Your lighting comes out to 2.4 watts per gallon. It tried with 1.4 watts per gallon on a BTA and nearly lost it. I will start to shrink, maybe bleach, then die. Mine got to be the size of a golf ball. I upgraded lighting to 6.9 and watched in 3 months it grew to the size of a softball and then started to split. I've had other changes and upgrades since then and have several anemones.
Been keeping BTA's for 4 years now.
As to the problem with it being in some rocks, this can happen, but I would like to know how you acclimated it? Where did it come from? Local purchase or Mail order? In my opinion it takes at least 2 weeks for an anemone to get used to your water conditions, this does not include walkabout time as it will wander about your aquarium looking for a rock and crevase to put its foot in and other water conditions that it likes.
What do you mean by yellow tentical? They are not supposed to be yellow.
Can you give me a pic?
Thomas