Stony corals progressively bleaching - What am I doing wrong?

[Eackone]

I have a 450 RS Reefer (90 gal display; approx 116gal total)

It is a mixed reef with no new introductions in 2020. It is mostly comprised of various Zoas, Montiporas, porcilopora, 2 large toadstools, a large elegance coral, mushrooms and a few chalices.

I have a Maxspect R5 Light and I dose Aquaforest components 1+2+3+

Over the last few weeks, many of my stony corals (montis, chalices and my 2 acro frags) have been progressively dying/receding/bleaching. I've been actively fighting with a bit of Dino/Cyano but it does not seem to be smothering the corals. Its mostly on my sandbed.

I've been testing actively to try to find the root of the problem and I haven't been able to pin it down.

Salinity: 1.025 - Pinpoint Salinity monitor
Temp: 77-78F - Apex probe
Ph: 7.8-8.1 - Apex probe
Kh: 8.5-9.1 - Aquaforest
Ca: 400-420 - Aquaforest
Mg: 1500 - Aquaforest
No3: 1 - Aquaforest
PO4: 0.03 - Aquaforest (Crept up to 0.05 lately but I added a bit of gfo)

I have a few theories:

1) The dino or cyano is affecting my more sensitive corals in a way I am not aware.

2) The large toadstools (who seem to have grown a lot lately) are affecting my sensitive corals - I added 1.25 cups of carbon on Sept 7th but have not seen improvement

3) Too much CA variation?


Any input would be greatly appreciated. I'm at a stage where I'm considering making my tank a Softie only reef

 

[WIReefer]

How long has the tank been running? Also did you start with live or dry rock?

 

[Charlie’s Frags]

According to Brs those light have terrible spread and an insane hot spot if mounted to the manufacture recommendations. I also think you’re stressing/starving them by stripping your po4 too low with high alk

 

[Eackone]

Thanks for the input.

My tank has been running for 2-2.5 years. It was started with a mix of live rock and dry rock (about 40% live rock).

I've never really changed the settings of my light since I first set it up (i had taken some settings from this forum if I recall). Everything seemed to be doing fairly well.

Considering I'm also struggling with Dino I wouldnt be suprised if its PO4/NO3 Related. I was just under the impression softies had a higher PO4 tolerance than most stony corals.

Should I perhaps let my PO4 rise? or just lower the alk?

 

[Charlie’s Frags]

Thanks for the input.

My tank has been running for 2-2.5 years. It was started with a mix of live rock and dry rock (about 40% live rock).

I've never really changed the settings of my light since I first set it up (i had taken some settings from this forum if I recall). Everything seemed to be doing fairly well.

Considering I'm also struggling with Dino I wouldnt be suprised if its PO4/NO3 Related. I was just under the impression softies had a higher PO4 tolerance than most stony corals.

Should I perhaps let my PO4 rise? or just lower the alk?