Help! Peeling acros

[bluewhale]

The acropora in my tank are peeling in patches (not uniformly) and turning white (about 20% of surface area over the last five days). There are two colonies -- one pink and one tan with blue tips. Is there anything else I can do to test or adjust or should I leave well enough alone? Any advice would be greatly appreciated!

Recent changes:

- Over the weekend, I increased alkalinity from 5 dKH to 9 dKH in four steps over two days with Waterlife SeaBuff. (The buffer had been sitting around for more than a year and was partially caked, but I used it anyways.) Was that too fast a change? Perhaps there is something bad in the buffer?

- I also did a water change (about 12%) and accidentally raised the salinity from 1.024 to 1.027 SG. Have since brought it down to 1.025.

- Dosed with kalkwasser for a few weeks and stopped this weekend after I realized my calcium levels were really high (from a new bucket of salt). I am waiting for some of the calcium to get used up and plan to continue to add carbonates to achieve a better balance. Perhaps this has affected my pH that the test kit is not detecting?

- Siphoned most of a layer of diatoms off the back glass and siphoned off quite a lot of detritus.

- Installed another powerhead (but not close to the acros).

- Added a big euphyllia ancora (hammer coral) on the other side of the tank.

Current chemistry:
- Ca 580 ppm
- dKH 9
- Mg ~1200
- SG 1.025
- NO3 <xxx (not measurable)
- pH: According to Hagen Nutrafin pH II test it is 8.3. According to Sera pH probe it is 7.8-7.9, but it is an old probe that was dried up for a few months before I calibrated it and put it back in. I have been able to see from the pH probe that pH has been gradually trending downward, and this has become more apparent after I stopped using kalkwasser.
- ORP: After the siphoning, the ORP went from 250 to 360.

I use Prodac Ocean Reef salt from Italy with dKH 9, Mg 1280. The Ca is really high and measures >700 ppm with three different brands of test kits including Prodac's own kit (but not Salifert, which is not available here).

I set up a new tank in August and so far no problems. Before that, the acros were in a dirty-looking, neglected tank with no sump and a big canister filter that didn't get maintenance for months at a time, and they did just fine. I was using CoralLife salt then. All specimens made the move okay and the acros were growing in the new tank. Could I have been tinkering too much, and not too carefully at that?!

It is hard to get acros in Hong Kong, so I would really like to save the two I have if possible.

Thanks!
Bruce

 

[NaH2O]

The jump in salinity would be stressful combined with the on them....how many days between the accidental spike in salinity and you bringing it down to normal levels? You can put a ring of superglue gel around where the healthy tissue starts to try and stop the tissue from continueing to come off. At least that's what I would do. Were you using a hydrometer or a refractometer to read your salinity? Did you have a big shift in pH when you were dosing the buffer?

 

[NaH2O]

oops, I forgot to mention, also if you can, frag the healthy pieces of coral off the dead skeleton, and see if you can stop the tissue coming off. When I had a coral RTN I fragged off as much as I could, ran some superglue gel around the bottom of the healthy portion and reattached it. Sometimes it works, but sometimes if the coral is too far gone it won't help.

 

[bluewhale]

Thanks, Nikki. That sounds more serious than I thought it was. I have never had coral die on me before.

I noticed the spike in salinity only an hour after it happened, so I brought it down suddenly too. Maybe I shouldn't have done that.

I am using Sera glass hydrometers that were cross-checked against a conductivity meter (that I no longer use).

There was practically no change in pH when dosing buffer, either immediately or longer-term.

 

[NaH2O]

Is the tissue still peeling off the corals or has this stopped? IMO, anytime tissue is coming off a coral, it is serious, as the coral is under/has undergone some stress. When you say there are patches of peeling tissue, are they mainly on the branches, or at the base?

 

[bluewhale]

I just got home from work and looked again. A few branches are white halfway down, and some of the branches are just white near the tips. Where the white part ends there is a distinct change to the colored part -- not gradual. That said, I looked more closely and I'm not sure, but I think the white parts still have polyps. There is also one branch that still has a little bit of mottled color, so maybe it is just losing xooxanthellae and it is not the flesh peeling off. I think I will just wait and see what happens!

Thanks so much for your advice, Nikki. I noticed that you help many people here!

Bruce

 

[NaH2O]

Sounds good. I was under the impression that the corals were loosing tissue, sorry about the misunderstanding. Let me pull a quote from "Book of Coral Propagation" by Anthony Calfo, page 422 - Bleaching of Coral Tissue for Non-Pathological Reasons...

Stressful manipulations of physical parameters, especially sudden, are known to induce this condition. One such catalyst in the practical application of aquarium husbandry is drastic change in salinity, like the sudden influx of freshwater for evaporation top off. This can be mitigated by the common reality that such water is often unheated, and sometimes added in excessive quantity when neglect of evapoative loss, or failure of an automated device, "requires" that an aquarist add a significant amount of freshwater to correct the salinity and resume proper operating levels for pumps.

I know your reasoning wasn't due to evaporative loss, however, I think the above quote can be applied to your situation.