Acro tip recession

[Dans85]

I noticed yesterday that one of my small acro colonies is starting to recede at the tips.it has also been excreting slime from the effected tips.I have had it for about 3 weeks, and it's been high up in my BC14 under LED lighting. I'm not seeing any signs of pests. I have recently started dripping kalkwasser. I have observed alk swings from about 8dkh to about 7dkh over a 24hr period as per the API test kit. I have 7 other acros that are in the tank that are showing no signs of stress, only this one. And while I'm at it, can anyone ID this acro for me?

 

[DiscusHeckel]

If you are adding calcium hydroxide, I would expect alkalinity to go up not down unless you dosed too much too quickly. This causes precipitation and changes alkalinity and calcium levels. Acroporas react differently to unstable conditions. RTN/STN and burned tips are usual reactions.

 

[71xlch]

burnt tips

burnt tips

Looks like burnt tips. Maybe ALK is swinging more than you think when adding kalk.

 

[ajcanale]

I wouldn't trust API test kit for Alk when it comes to keeping SPS.

The most common cause I know of for what you've described and pictured is high alk paired with low nutrients.

IMO get a better test kit to know for sure.


Edit: I'd say likely A. formosa or yongei

 

[Pife]

Did you just get this piece? That could have been caused by shipping.

 

[risin]

I wouldn't trust API test kit for Alk when it comes to keeping SPS.

The most common cause I know of for what you've described and pictured is high alk paired with low nutrients.

IMO get a better test kit to know for sure.


Edit: I'd say likely A. formosa or yongei

This was my issue, had an alk swing too high and lost a couple sps. Tips would recede just as your pictures show and then they would die rapidly after about 5 days. I also noticed that polyp extension was nearly non existent after the tips showed damage.

 

[Dans85]

I've had the piece for a few weeks now. It was in my tank for about two weeks before I noticed any signs. The tank is definitely not a low nutrient system, I feed a cube of marine cusine everyday, this is in a BC14. One thing that I noticed is that none of the other 9 sps pieces in the tank are showing any signs of stress whatsoever.