Duncan Coral not fully extending

[Dryan]

Hi Everyone,

Looking for some advice on my Duncan coral. I got it on 4/20 and it was a very small frag, the coral has since grown another head. After lights out a week ago the new head closed right up and has barely changed from the image, while the main head has only opened up about as much as shown.

Tank is 3 months old

Alk: 8.5 to 8.8 (Aqua Forest)
Calcium: 455 - 460 (Aqua Forest)
Magnesium: 1350 - 1400 (Salifert)
pH: consistent from 8.0 to 8.2 over the course of the day (Seneye)
Temp: 78 (Multiple)
Nitrate: 6.0 - 7.2 (Hanna HR Nitrate)
Phosphate: 0.024 - 0.046 (Hanna ULR Phosphorous)
Ammonia: 0.001 to 0.005 (Seneye)

I've been dealing with Dinos but the worse is mostly over, using UV, dosing nitrate, phosphate, and plankton. I was having an issue with nitrates where about a month ago they were at 8.0 and slowly declined to 6.0 as of 6/1, from then I've been dosing extra nitrate to increase and have reached 7.2. Phosphate has been relatively stable, but not super stable.

No other corals are showing signs of distress, and most are showing signs of growth. I was target feeding reef roids, but stopped on 5/18 due to the dinos. I just started target feeding Ultra LPS Grow & Color Medium Pellet - Fauna Marin which the main head gobbled up 1 pellet two days ago, but showed no relative change in openness.

Fish:
Two about 1 in clown fish,
Black Molly

My current thoughts are the slow dip to 6.0 Nitrates, and mild instability with phosphates caused stress for the Duncan and hopefully slowly raising nitrates to back 8.0 and stabilizing phosphates more will fix it but wanted to see if anyone else has any advice.

Images are today after lights on and this morning before lights went on:

 

[T-J]

Tank is 3 months old

So, based on your timing, you put the Duncan in your tank when the tank was about 1 month old....so basically, maybe, just out of cycling.
Corals may take time to show signs of stress, and it's possible that your Duncan is now showing stress from being in the tank at an early age.
Get your tank stable before you add any more corals. Duncans are pretty bullet-proof, so it should be ok if you can get your tank stable.

 

[vetteguy53081]

Get this coral to mid tank under moderate light and water flow. The dino issue would have upset this coral. Feed 2-3 x a week. I feed mine mysis shrimp.
Assure salinity and temperature not elevated.

Mine:

 

[Sharkbait19]

At this age of the tank, it isn’t so much about having the proper parameters (which is, of course, important), but more so about having a ton of nutrients in the water, which stony corals especially thrive off of.

 

[Sharkbait19]

Double post

 

[Dryan]

Lighting is about 100 par measured with seneye, flow is moderate-ish I have an mp10 on the opposite side of the tank and bits of hair algae around it gently sway. It's been in the same spot since 4/20 with no issues prior. Should I try spot feeding reef roids to get the nutrients to it?

 

[Sharkbait19]

I’d see about moving it around, could help.
Feeding can make a difference, though closed up corals don’t always have much of a feeding response.