What happened???

[jazzfisher]

Yesterday these 2 corals looked like this as the lights were getting ready to go to moonlight.. when I checked the tank again before bed. The larger purple one was gone the plug looked as if it had shrunk to nothing. This morning it was still the same and the lighter pink one looked pretty sad. This evening it almost looks like the stem of the pink one is “breaking”. I did a water change yesterday and the only thing I added with the water was Prime. All fish & other corals are looking good. No new corals, fish or inverts have been added for several weeks.
Sorry about the second photo.

Thanks for any help.

 

[BiGGiePauls33]

How old is your tank? What are you parameters?
Edit* Prime is a tap water conditioner and I personally don't use it or products in my reef tanks. My suggestion would be to either use RO/DI water you've made from home or bought from you LFS. As far as the corals go, what was your specific gravity and alkalinity in the tank and also what were they in the water change? How big is the aquarium and how much water did you change out?

 

[jazzfisher]

I have IM 30 L, original tank started 4-5 years ago-transfered to this tank in May. My water is from LFS, I changed about 1/3. The salt & temp are 78 degrees & 10.25. Very steady.
PH 8
Ammonia 0.25
Nitrite 0
Nitrate 10
Cal 500
Kh/Alk 9
Phosphate 0.25
Mag 1470

Thank you for trying to help! This morning when I got up the pink one still had a stem although bent over-by the time the lights came on fully (an hour or so later) there is nothing left but a pink stub.
Photos of other coral from right now: Note only turned up the white for the photos-don't have that much white light.

 

[reef lover]

Id find the source of the ammonia. Most likely thr issue.

 

[Arcticfirefighter]

+1 @reef lover, you have to find the source of that ammonia and get rid of it. That will wreak havoc on everything eventually.