Random corals dying

[150 Gallon Reef]

Hey all,
I have a 100 gallon IM Marine mixed reef tank with approximately 20 to 30 gallons in the sump. It has been up and running for about 4 months now but had rock transferred from my other system which was up for about 2 years.
I notice some of my corals end up dying ogg slowly for no apparent reason, which others flourish and grow almost daily. Reefbreeders photon 48 v2 for lighting. Reef octopus skimmer

I have had 2 plates die on me in the past 2 weeks out of random. The one I had for 2 years also. Could too much flow cause issue?
Also have a mini colony of jkr rainbow on my frag rack which is doing great! But the frag from the exact same colony, Is dull and has almost a grey look to it. The frag was fully encrusted and looked great at one point. I also kept the frag right next to the colony. I also can't keep millis alive for crap.
I have plenty of other sps such as montis, walt disney, shortcake, pink caddy, cherry bomb, ect, which are doing great. What could be some issues causing these things to happen to some corals? I have a doser with doses alk and cal daily and I dose potassium nitrate (stump remover) every 4 or 5 days due to my nitrates bottoming out if I don't. My levels are as followed:
Nitrate 4-8ppm red sea
Phos .04 to .08 hanna
Mag. 1450 red sea
Alk 7.8 to 8.2 red sea
Cal 450 redsea
Salinity 1.025 refractometer

 

[Ron Reefman]

What setting are you using on the Photons (I use them too). How deep are the corals that are dying? How do they die (slow or fast, from the base up or all at once...)?

#reefsquad

 

[150 Gallon Reef]

What setting are you using on the Photons (I use them too). How deep are the corals that are dying? How do they die (slow or fast, from the base up or all at once...)?

#reefsquad

I run 100 percent royal blues and blue for 1 hour. They ramp up and down after the 1 hour. Max whites are 25 percent during the same hour as the blues. The corals randomly die in any part of the tank. The plates died from the underside and slowly withered away. The sps can both die from the top or base. Sometimes in random places. When the jkr turned greyish, it happened slowly

 

[Ron Reefman]

I wish I could help, but I'm stumped. Your PAR should be fine with the Photon used at those setting. Lets hope somebody will have suggestions.

 

[iamacat]

What’s your pH?

 

[150 Gallon Reef]

What’s your p

pH is 8.21 using a monitor

 

[iamacat]

Hmmm any evidence of pests on visual inspection?

 

[iamacat]

ICP Test would not hurt to get a solid idea

 

[150 Gallon Reef]

Hmmm any evidence of pests on visual inspection?

No visual of any pests. I dip every coral that has been looking iffy in revive, iodine or dr gs red bug killer

 

[150 Gallon Reef]

ICP Test would not hurt to get a

What is the best icp test you have seen/used? I see a few options on BRS and not sure which is best

 

[iamacat]

What is the best icp test you have seen/used? I see a few options on BRS and not sure which is best

Triton and ATI have been the top scored from what I have seen. Triton is what I have selected to use for no particular reason

 

[2Wheelsonly]

What’s your pH?

Wondering why you ask this? I have yet to see ANY evidence of pH causing corals to die. Chasing pH with a controller/probe seems silly (mainly why I ask). There are folks out there with long term success keeping corals at 7.6-7.7 and I have never ever heard of a "house not capable of keeping a reef tank".

I wouldn't chase lighting either, if you're losing random SPS then you have a pest. Find the pest... if your params are stable and nothing has changed then it's not params. I think reefers want to assume issues are black and white and it's a simple chasing of parameters when the real and more difficult issue is identifying and eliminating pests. The only params I feel are worthy of testing are whether your nutrients are too low.