Corals struggling. At a loss as to why?

[ScubaSkeets]

Hi folks!
I'm at a loss.
My corals are not doing good.
PH: 8.2ish (digital meter)
Salinity: 1.026 (refractometer)
Ammonia / nitrite: 0 (Salifert)
Nitrate: 2.5 (Salifert) (Too low?)
Alkalinity: 9.7ish (RedSea)
Calcium: 450 (RedSea)
I haven't tested Magnesium lately because the last times I did test, it was 1600+, but from what I've read, RedSea is known for high readings.
PAR: 180-200

Initially, I had a rock full of fuzzy mushrooms. It also had 2 red BTAs. It was doing good. I then added another rock with some red BTAs (from the same LFS/same tank) and soon after my mushrooms started to "poop" and melt away. I removed the 2nd rock. I eventually started to add a few frags (LPS and SPS) and they are really struggling.
The only things I can think of is either the Nitrates are too low, or there is something in the water causing this. I am planning on doing a huge water change today, but is there anything else I should check for/do?
Thanks!

 

[WIReefer]

Whats your PO4? Also are you using Rodi water?

 

[Timfish]

In addition to WIReefer's questions, how old is your system? How did you establish the ecosystem: dry rock, life rock, aquacultured live rock (just nitrifying bacteria) or maricultured live rock (sponges, fungii and microbes that can't be cultured)? Do you have any fish and if so how often are you feeding them?

 

[jeffchapok]

You can always add some carbon to remove anything from the water that might be irritating your corals.

 

[ScubaSkeets]

Phosphates are 0 per API
I am using RODI water.
The tank has been up and running since around Sept 2020. I have five fish, all doing well. It started out as a FOWLR and I established it using life rock and 2 clowns (still thriving).
I did originally begin with IO salt, but have been doing 30% water changes with RedSea Pro black bucket (I know it has high alkalinity, but my wife uses it in hers and her corals look great!)

 

[Poof No Eyebrows]

How close are the nems to the corals? Have they moved around and possible stung some things along their way?

 

[ScubaSkeets]

You can always add some carbon to remove anything from the water that might be irritating your corals.

So, I started with a canister filter, but recently switched to a sump. I am still using my canister at the end of my sump with the lines going in and out of the return tank. In there, I have carbon and Chemi-pure. Should I take a bag of carbon and drop it in the small chamber in the sump instead?

 

[ScubaSkeets]

How close are the nems to the corals? Have they moved around and possible stung some things along their way?

The nems have not touched the corals as far as I can tell...unless they are very sneaky when I'm not looking

 

[Tokash23]

What sort of light are you using? I know you said par from 150-200 but how did you measure it? Im no expert on lighting but just a thought maybe they are getting more light than you expect or not enough maybe. That would be my thought process as it seems everything else looks in order. Good Luck

 

[nereefpat]

What about some details for lighting and flow?

 

[MabuyaQ]

Low (no) PO4 and high Alk may be the cause of your issue, but for this we need the results of a more accurate PO4 test.

 

[ScubaSkeets]

What about some details for lighting and flow?

I am using 2 AI Prime HDs
Par is measured using an Apogee SQ-420.
Flow is by return line, and two power heads on each side of the tank

 

[nereefpat]

I am using 2 AI Prime HDs
Par is measured using an Apogee SQ-420.
Flow is by return line, and two power heads on each side of the tank

What are the dimensions of the tank?

By struggling, do you mean dying, or turning brown, or just not growing?
What kind of corals?

 

[jeffchapok]

So, I started with a canister filter, but recently switched to a sump. I am still using my canister at the end of my sump with the lines going in and out of the return tank. In there, I have carbon and Chemi-pure. Should I take a bag of carbon and drop it in the small chamber in the sump instead?

What you have should be okay. But you can never have too much carbon, so if you have the opportunity to add more, do it. I have a total of four bags hanging in my setup at various points.

I think your problem may actually be your extremely low to zero PO4 level. Some level of phosphates and nitrates are necessary nutrition for corals. Soft corals, such as mushrooms, especially like "dirty" water. My PO4/NO3 consistently runs .5/50 ppm and I have mushrooms growing everywhere.Your mushrooms may be slowly starving.

 

[ScubaSkeets]

Thanks for the replies.
I was running alot of filtration, so as of last night I am only running filter socks, ceramic balls, Matrix, carbon bags and Chemi-pure. Hopefully it will "dirty up" the water some.

It's a 54G Bow Front. Here are some pics of the frags:

Duncan:

Pipe Organ:

Zoa rock:

Toad Stool (?):

Mushroom:

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