Help with Acropora

[Lapras]

Hi all,

I've had this acro for about 9 or so months. Anyways, there was a point where it started to encrust and grow, then it kinda slowed. I noticed that although it's keeping some color, the polyps on one side are not showing and the skin has this almost "chalky" hue to it. I also noticed parts of the skin slowly fading/browning.

The rest of my acros seem to be fine, and are growing/encrusting. Any ideas of what this could mean or indicate?

sg: 1.026
nitrates: not detectable
po4: 0.06
alk: 9.5 dkh
ca: 480ppm
temp: 79F

Lighting is 3x hydra26, PAR for most the acros sits around 135-205 using LED specific PAR meter. Photoperiod starts 12pm, ramp highest to 1pm, then slow decline to 9pm, off at 11pm

Here are some pics. Thank you all in advance.

 

[saltyfilmfolks]

Has the flow changed now that other corals have grown out?

You might need to consider no3 dosing or a feed suppliment. Aminos , Red Sea colors etc.

 

[Lapras]

Thank you for the reply. I have not changed flow in a long time. I forgot to mention I do dose aminos about twice a week.

 

[Charlie’s Frags]

Alk is too high and par is too low. Slowly bring your alk down to 8-8.5 and slowly crank those hydras up. Are you using gfo or carbon dosing?

 

[Lapras]

Yes, I am using about 40% of recommended GFO dosing via reactor. Didn't want to put too much in there. No carbon

 

[Lapras]

And also: Although the other acros are growing/encrusting, (albeit slowly), do you think lowering ALK slowly will be good? is 9.5 dkh too high because of the lower nutrients or? Thanks again

 

[saltyfilmfolks]

I wouldn’t change the system if only one coral is having issues.

The reason folks run higher alk is to grow coral faster. You just have to keep nutrients up.

 

[Charlie’s Frags]

Yes, I am using about 40% of recommended GFO dosing via reactor. Didn't want to put too much in there. No carbon

Did this start after the gfo?

 

[Lapras]

No it has been a couple months already passed since using the GFO. Maybe it's the GFO? Also, I just recalibrated by Apex pH probe with 7 and 10 solution... The prob is telling me my pH is 7.06!!!! I'm going to buy a pH tester and check, but if this is true, then this might explain a few other nuances in my tank.

 

[Charlie’s Frags]

No it has been a couple months already passed since using the GFO. Maybe it's the GFO? Also, I just recalibrated by Apex pH probe with 7 and 10 solution... The prob is telling me my pH is 7.06!!!! I'm going to buy a pH tester and check, but if this is true, then this might explain a few other nuances in my tank.

I’ve only checked my ph once in the last year. But I know all my sps slowly withered away like that when I used gfo and had low par from my hydras.
I got rid of gfo and nopox and almost tripled my par and my acros started surviving and growing. No more gfo or nopox for me. I actually don’t even have a skimmer anymore

 

[Lapras]

Ok, so I shut off the GFO, and re-calibrated pH , which has been around 8.1-8.2. Also bumped up lights by 10%; Saw more PE than I usually do, so might be a better sign.