Bird of Paradise polyps all suddenly retracting after water change

[Josh009]

Hi Guys,

I have a couple of ORA bird of paradise frags, both on the same plug, that have been doing quite well for the past few weeks I've had them in my ~6 month old 50G tank. They're my first SPS besides an encrusting montipora that's in the same area of the tank. the bird frags are in a fairly high flow area about 18-20" below my lights (single AI Sol blue).

I did a ~15% water change this morning and nearly immediately these corals - but not any of the LPS and softies in the tank - started retracting. Over the following few hours, I've been seeing more and more of the green skeleton and less and less of the polyps.

Here's what they are looking like now:

(best picture I could get with my iphone)

water parameters are
SG 1.026
Alk 7.3 DKH (a little low, I know)
Calcium 420
Mag 1530

Any thoughts on what I can/should do in this situation? Thanks.....

[leonel619]

maybe the parameters on the new water u used for the water change were very different from those in ur main tank??

[Josh009]

I don't think so, salinity was spot on and temp within a degree or so. It's the same bucket of Red Sea Coral Pro salt I've been using for a few weeks. and the water was mixing with a powerhead for more than 24 hours. But obviously the water change had something to do with it.... my current plan is to not mess with anything and see how it is tomorrow. I fear if I screw around with anything I'll just make matters worse.

[jason142]

So the salinity was the same so what about the Calcium, Alkalinity, and Magnesium. How long ago was your last water change?

[Josh009]

Unfortunately I didn't test the tank water before the WC today. Last one was about 8% on 7/10, just before i went on vacation. But my previous tests were on 7/4, and the parameters were pretty much the same. I typically do that ~8% change every Saturday. BTW, I also use kalk in my ATO, for the past ~3 months, which is added at less than 1/2 gal per day. That's always allowed to sit for at least 12 hours before use. Particularly today as I've watched that coral suffer, I've been considering quitting kalk in favor of a two part setup....

[jason142]

It would be my guess that the parameters of your display and your mix were way off.

[Josh009]

if that were the case, do you have any recommendations on an action plan? thanks....

[jason142]

Not really, test your levels now and see where they are at.

[Josh009]

I did test a few hours after I noticed the problem, they are in my original post. Very close to my last tests.

Do the sps retract then recover? Perhaps only time will tell and this is another lesson I have to learn as a beginner.....

[jason142]

Mine have from time to time. If your parameters are pretty constant then they should be fine. Is it all the bn or just the one you took a picture of?

[Josh009]

That one, but it's the only one I've tried so far. I'm hopeful it will recover.

[Josh009]

Well the lights are still off, but the branches look nice and fuzzy for the most part, from what I can see... I think they are recovering! I'm stoked. Hopefully they will be looking good when I get home from work.

[JohnnyAirtime]

It would be my guess that the parameters of your display and your mix were way off.

That's exactly what the problem is/was.

The water change didn't mention being tested for Alk/PH...etc. Temp and salinity are only 1/8th of the tests if you want your water change to be spot on. Any deviation from your tank water, to the change water will "shock" the coral(s).... even a tiny bit of change in PH or Alk.

Josh...
The coral isn't "recovering" per-se... it's just getting used to it's newer water parameters. It'll be fine.

[Josh009]

I guess I've made bad assumptions about the sensitivity of the corals to differences in the new mix vs tank water. I'll do more research around this. Do others run a full battery of tests on tank and new water at each change? I haven't come across that yet.

It also sounds like sticking to smaller changes like the 8% I was previously doing will lessen the chance I'll create these negative effects with water changes.

Thanks all for your input.....

[JohnnyAirtime]

I rarely test my water... maybe, every 4 months.
... and, I do water changes in mass number of gallons (every 2-4 months). Never a problem.

Yet, if a coral closes up for a few days... I don't panic, either.

I do have a Goniopora that'll let me know when my water change was drastic, or when it needs to be done.