Green hydnophora dying, please help

[Bret Brinkmann]

I have three small pieces that have attached to my life rock and were doing very well for about a year. Full polyp extension, bright colors, and growing. My GSP stopped coming out and I had a lot of red and brown hair algae build up. I checked parameters. SG 1.027, pH 8.3, alk 13.5, ammonia, nitrates, nitrites, and phosphate 0.0, Ca 420, Mg 1320. 29 gal tank with 10 gal refugium. 20K LEDs. At this point hydnophoras are fine.
SG and alk were high so I changed out about 2.5 gals of water for fresh RO water twice over two days. Hydnophora seemed okay at that point. SG dropped to 1.025 and alk to 12. Ca dropped to 200. Have been adding Ca everyday since. Checked a few days ago and it's back up to 400.

Day after the second water change, I cleaned out the hair algae, red and brown. It was thick and everywhere. Pulled off a ton from the rocks. Corals always did better after this in the past. Only difference this time was I used a toothbrush to scrub most of it off the live rock. This kicked up lots of sediment that was similar in color to my sand. Tanish grey. Hydnophora shrunk up like it normally would during an algae cleaning only never came back out. The GSP is doing well again but not the three hydnophoras. Now they are losing their color and shriveling up. It has been a little over a week since I scrubbed the rocks.

What is going on and is there anyway to get them healthy again?

 

[Tahoe61]

Hydnophora is a hardy coral, alk is probably too high, and obviously it's not stable. How do you measure SG? Do you have values for nitrates and phosphates? Did you do a water change after the scrubbing?

 

[Bret Brinkmann]

The alk was/is stable and high for several months. It only changed because of the water change. Keep in mind I changed saltwater out for freshwater to lower th SG. Which was also high for a long time. Neither being high for that time hurt the coral. It eventually did effect my snapping shrimp and brittle stars in addition to my GSP. Dropping them helped them all out and they are in good shape again.

I use the swing arm for SG. Not very accurate but very repeatable. My SG was actually 1.028 not 1.027. I will update my first post. Phosphate and nitrates are listed above and have not changed.

The water was changed, with fresh, before the scrubbing. I did not change any afterwards.

 

[Bret Brinkmann]

I am going to try dipping them in Furan 2. I will also dose some aminos and nitrates. I may also do a water change depending on the readings I get today.

It is hard to tell if their condition has stalled or gotten worse. Hopefully the Furan 2 dip won't hurt anything else as they are attached to the rocks. Does anyone have experience with Furan hurting other inverts?

 

[Sobo's Reef]

In the future... always do your tank cleaning first aka rock scrubbing... then do a water change afterwards to try and get any debris out. Don't start dosing on a whim.. do the water change first and see how it is after a day or 2

 

[Bret Brinkmann]

Performed the dip but used the Red Sea iodine dip instead of Furan. The hydnophoras got the mucus layer as indicated in the instructions. I also have been turning off my return pump at night when I add the Red Sea aminos and phyto/rodi/oysterfeast. I let that sit over night and the next day they were beginning to look less bad. It has been about a week now and they are all improving at slightly different rates.

They still have a little color to them and it is starting to comeback even more but slowly. Today I noticed they have what looks like little holes in their flesh. Still no polyps, but one has a few nubs starting to form. At first I reduced my light on time to half of what it normally is. Now it is back to 11 hrs a day.

They look the best in the morning right after the lights turn on. The GSP even seems to prefer this return pump off at night situation. It comes out fully right after the lights come on but a few minutes after I plug the pump back in it will pull the polyps back in until tomorrow.

I am going to test the water again tonight both before and after the feeding/amino dosing. I think there is something about that condition that is not present normally that would benefit all the corals. I also noticed my brittle stars really liked the reduced lighting and feeding schedule. They came out in the open for nearly the entire lights out period. Unfortunately two of them somehow climbed the side of the glass, which was clean of algae and debris, and Texas chainsaw massacred themselves. One did so several times... So I have an MP10 with screens coming to help prevent that as my Koralin powerheads aren't safe for them even way up high.

Still not entirely sure what caused all of this but leaning towards the alk change. Did anyone else experience this sort of damage to an SPS after an alk swing?

 

[Bret Brinkmann]

Update: The hydnophoras were stable I think, up until I cleaned the algae of the glass and rocks again. This stirred up some more sediment. Then they started with the STN again. I dipped them again and did a roughly 5 gal WC. System is 29 DT+ 10 fuge. Still doing the pump off at night with feeding. Also tilted the LEDs towards the GSP and away from the hydnophora for the entire lights on period.

The GSP is loving life right now. I suspect it was the water change. The hydnophoras are looking like they don't have much flesh left. I can see the skeleton inside. They still have color but the flesh is just that thin. The edges are brown and there is still some green left in the middle but it looks mostly bleached. So I am giving them less light because I am concerned about light stress in there weakened condition. I don't know if it is helping or not. More holes in the flesh though. I'm wondering if the sediment is precipitated Mg or Ca and too much landed on them during cleaning. Sort of like salt getting on an anemone? I do have clumping sand. I read that this could be a sign of precipitation. I am researching this now. Hopefully my experience will help someone in the future.