Phos is a little elevated but not a cause. mature tanks of 6 months best but BTA can do well in a 3 month tank, However a 3 month tank is subject to chemistry changes such as ammonia and nitrates and at a stage where water changes are certain and BTAs do not favor these changes. I believe your light is the issue here-Insufficient.
Monitor water regularly to assure there are no major changes. Ammonia and nitrate levels should be safe verified by using a good quality test kit and Not API either.
Here are some water parameters to follow.
- Water temp: 77°F - 80°F (stay close to the middle of this range)
- pH level: 8.1 to 8.3
- Alk: 8 to 11 dKH
- Salinity: 1.024 to 1.025
- Nitrate < 5 -10
- Phosphate < .04 - .08
Most anemones tend to move around the tank until they find a suitable spot and if starts to move , simply direct flow towards the nem. Anemone lighting is an important part of their care as they need good light to thrive because they’re photosynthetic and absorb light to produce their inner food and growth cells known as zooxanthellae in their body which they feed on. Without adequate lighting, the anemone will expel the zooxanthellae which many think is poop and turn white which is bleaching and often leads to their death.
A moderate amount of flow is recommended as well as moderate light. Too much flow will cause the anemone to stretch out and look stringy. Keeping things moderate will help avoid this from happening. Avoid directing your flow directly at the anemone which stresses them.
Assure your light is moderate and flow is not excessive in your case. I again believe light is inadequate. Consider an Ai 26 or 32hd, or even noopsyche which will satisfy their lighting needs
RODI is a must and even water from the refill stations at walmart will suffice.
Tap alone has ingredients such as chloramines, lead, zinc and others and just not worth it . water conditioners such as Prime will dilute certain elements but not remove them.
RODI is the way to manage water which is the lifeline of all our specimens in the tank