First ICP complete. Want to confirm next steps

[WRXgucci]

TLDR Biocube 32 running for 6 months, 2 clowns and a gramma, been adding some zoas and euphylia and they are gradually becoming more not happy. Trying not to lose coral. Ive had 2 zoa frags look nice and healthy 1 day, then close up and slowly shrink to nothing now.
Been doing weeklyish testing with hanna tesers to keep parameters in check. Did an ICP to verify my hanna testers and check more parameters. Phosphate seems to always want to rise. I see guidelines of being under .1 and Randys post suggesting sub .3. ICP has confirmed my hanna tester of being in the .4-.5 range. That is the only parameter that seems out of "spec". When I got my phospate tester in 2 months ago, I was getting ~.7 readings. I have been slowly bringing it down however when running gfo coral seems to be even more upset, but I assume thats more due to the phosphate dropping rather than anything else.

The questions:
Do I continue to slowly run GFO to gradually bring my phosphate down below the .3 range? What timeline should I aim to reduce phosphate from say .5 value to .3?
I am currently testing temp, salinity, alk, nitrate, phosphate. What should be the next tester on my list to pickup? Im thinking ph?
What else should I be looking for to keep my coral thriving?

 

[KrisReef]

Folks who run ICP might have more input for you if you post the ICP test results (Link?) so they can see what the numbers are.

Also a picture of the unhappy zoa's, might not be a param issue but rather a pest?

 

[Randy Holmes-Farley Verified Community Expert]

I'd try to gently bring phosphate down, but it may have no observable benefit to do so.

 

[Mr. Mojo Rising]

gfo sounds fine to bring down the phosphates, but I don't think its a phosphate issue.. being happy and then closing and slowly shrinking to nothing sounds like low light issue. Pictures and more details on the tank (light and flow) will help.