Zoanthids not opening fully and discolored - Please help ID

[makingitwork]

For the past 6-7 weeks my zoas have not been opening fully, have their skirts pulled back, and are discolored.

Barebottom mixed reef 20g - Paired Clowns - Lawnmower Blenny - 20lbs live rock (2yo)

Sunny-D's (on rack)
Utter Chaos (colony)

I dose only calcium, fuel, and for the past 4 weeks have been dosing vibrant bacterial culture to help with the cyano visible in the images. I have eliminated most of my cyano as a result, but my zoas appear to still be struggling. I understand the Sunny D's are dirty in the image, but Utters have remained mostly clean as I blow them out often. I keep a minuscule amount of detritus in the tank, and there is little to no algae at this point.

My other corals are doing well, and the parameters are relatively stable.
I keep salinity high (1.26 ATO), use friz pro mix salt, and feed with rotifers.

I did have an issue with a pair of peppermint shrimp I had taking chunks out of my stylo, frogspawn, and blasto. I removed them 3 weeks ago.

I frag occasionally and have fragged off both colonies shown below. My utters were overgrowing their rock quite a bit and I could see a lot of baby polyps being shaded near the base around 3-4 months back.

I am unsure as to what could be the culprit.

*I would greatly appreciate if anyone can help point out possibilities I can try to check off some boxes.

 

[Reefing_addiction]

Lighting, flow, nutrients

 

[makingitwork]

@dyerrm​

Lighting, flow, nutrients

Took my water for a test about 5 weeks ago, the only things out of the normal range was my alk and ph.

Dosed regularly since then,

Tested today, alk Is low as well as ph. I know that alk and ph are correlated, could this be a probable cause for the zoas? I also added a lot of SPS since my last check as well, I think maybe the tank is just consuming more than it used to and I have to up the dose slightly.
Alk - 6
Ph - Very slightly low

 

[SauceyReef]

Ever figure out what happened?