infection, chem warfare or pest?

[TampaSnooker]

For the second time now, I'm having issues in a propagation system that houses LPS, z's and p's and corallilmorphs. The pattern of sickness is the same and onset is very fast. An uncut wall hammer suddenly retracted its polyps. It died 5 days later and the flesh just fell off of it in big, white chunks. Two days after its recession started, I had a couple large chalice colonies STN and all my Euphyllias (3 separate bins) retracted. Acans are closed up tight but hanging on and I've lost 1/2 my chalice frags - all healed and growing prior to this episode. Zoas are closed up and coralimorphs all expelling mesentary filaments. I did lose a rock anemone, but otherwise, crucifer, BTA and maxi minis are all perfectly unaffected. I think it was coral tissue rather than brown jelly protozoans on the chalices, since it didn't wash away, but the flesh peeled right off and very quickly. The two chalices that were lost were recent additions.

Chem is stable and within normal parameters, but there was an unexplained dip in alk when the wall hammer started to go. I've also had a sudden dip in temp down to 74 with this harsh Florida winter. I typically run at 8-9 DKH, but had an unexplained dip to 6 for a few days when the issue started. System volume is 400 gal and it is a fairly typical 3 tier store type system. The protein skimmer went nuts at night during the first die off back in September, which suggests Dinos to me.

I'm not sure if I am dealing with chemical warfare or a bug - toxic Dinos or Vibrio come to mind. Fresh carbon did not seem to help in either instance. A 40% water change seemed to accelerate it, which suggests a single cell bug. No pests came off of the affected specimens when dipped in Revive this time, but during September's carnage, there were 1000's of 'pods on the LPS; none this time. I did treat with Interceptor in Sept due to the number of bugs, thinking I might have vampire copepods, but I don't see them in numbers anywhere in the system this time around

The whole system is ticked off at the moment. I"m also noticing a dark green/brownish algae that came on quickly. Normal P levels are under .05 but I have surged to .10 with the coral death. I was going to bring samples of tissue and the algae to try to identify Dinos or protozoans but after a couple conversations, it seems that even if I can ID these critters, I may not know if they are causative or just feasting on the decay.

Does anyone have any thoughts on how to find the cause? This came on very suddenly.

[MechEng99]

Sounds like it is more of a water issue to me.

I've rescued hundreds of corals from various parasites, diseases, etc., and none of the symptoms I've seen match what you've described. Most of the corallivore pods only target a specific genus...or maybe a few genus. I've never come across one (in person or in research) that will go after LPS and softies. They also usually don't cause STN - it's usually more of a slow recession rather than necrosis. The flesh doesn't usually peel off.

I doubt it's dinos as they seem to target genus-by-genus rather than lash out on everything. You would probably also notice some macro-effects as well (brownish green snot-like stuff covering rocks). Vibrio usually causes bleaching first in LPS...not flesh peeling.

I would look to your system and water specifically. Are any inverts/fish affected? You said a water change accelerated the problem...any chance your RO/DI (assuming you run one) needs a filter change? Bad batch(es) of salt? Ticked off friend/customer? Stray voltage? Bad carbon?

What are the following:

Salinity:
Temp: (dropped down to 74*)
pH:
Alk: 8-9dKH, dropped to 6 dKH
Cal:
Mag:
Phos: 0.05-0.1
Amm:
Nitrite:
Nitrate:

[TampaSnooker]

Parameters are normal, aside from the previously mentioned dip in alk and temp swing 76/7->74, 1.024, pH not logged, alk typically 8-9, Ca 400, Mg 1400, Phos .05-.10, N not logged since there are very few fish in 400 gal.

It's not likely a water source issue as we also provide service to 30+ reefs around town and there are 3 propagation systems in operation here, too. Only 1 system shows these symptoms. We did have a vandal back in September, when I had similar issues, who was kind enough to dump fertilizer into the FW reservoir, along with 2 rock culture vats, but there is no evidence of similar contamination this time, since the rise in P is minimal and coincides with the scheduled GFO change.

There is a similar algae that popped up during both instances. it is green/brown and fuzzy, and just today there is some reddish brown snot that is appearing with bubbles in that system only. I'm going to try to harvest both and take to a Dr customer with a good scope and camera to see if I can get an ID. Fish are unaffected, snails don't tolerate this algae species.

After 4 days of running a small UV, the corals have stabilized, so that's happy.

"I doubt it's dinos as they seem to target genus-by-genus rather than lash out on everything. You would probably also notice some macro-effects as well (brownish green snot-like stuff covering rocks). Vibrio usually causes bleaching first in LPS...not flesh peeling."
-- but that's what's happening. Euphyllia, wall hammer, same species chalices - different colonies, Rhodactis reacting. No bleaching.