Came home to some problems / Advice needed

[novahobbies]

Hello all!

Wife and I had a few days "out of town" down in Key Biscayne for our 12th wedding anniversary and I have to say, we had a blast!

However...we came home yesterday to a few problems in the tank. I lost an entire generic pocillopora colony; it was missing tissue from the base to the tips (just the tips had any tissue left) and when I looked closer, I saw that there was some white areas on a couple birdsnests as well. Lastly, there are two white spots on my rainbow pocillipora that weren't there when I left.

At first I thought maybe the dead Poci was due to stress....it had been knocked off it's perch a few nights before we left, and I found it the next morning in the not-so-gentle arms of the tube anemone. So, I knew there was some tissue die-off from that before we left. However that's no reason for the other colonies to be affected.

All other corals, including 2 green Pocilloporas, Acros, Montis, Pagodas, Favites, etc, appear unaffected.

This morning I did a whole set of tests. I have a couple low numbers, but I don't know if any of these would trigger a RTN event! Here are the details:

110g Aquarium
Livestock: Midas Blenny, Potter's Angel, Mystery Wrasse, Dispar Anthias, Bartlett's Anthias, Mated Pair of Red Mandarins.
Turbo, Astrea, and Nassarius snails. Couple Florida conchs. NO crabs. A few Asterina stars.

Test Results:
Temp: 77F
Salinity: 1.026 / 34.5
pH: Between 7.8 and 8.0 API High-range test kit.
Nitrite: 0
Nitrate: 0
KH: 7 *
Ca: 400 *
Phos: 0>0.25 (closer to 0)
Mag: 1400ppm


So, here's my thought. I dose 2-part solution. Since I was gone for a few days (and I do have a decent number of stony corals) I can imagine that my Alk and Ca would be low. However my Alk seems VERY low, don't you think? I usually keep it around 10. Would that dip be enough to cause the ind of stress that I found? Is there anything else I'm missing that might have caused this?

 

[Kayo2289]

Have you added any other pieces of coral to your display lately?

 

[novahobbies]

Nothing recent. Had some zoas added about 10 days ago. Dipped prior to addition, and nowhere near the problem pieces.

 

[milesofreefs]

If your tank is usually stable that large of a swing in just a couple days could with out doubt cause stress in your corals.

 

[WhoDey64]

Have you watched your potters closely?

 

[gatoralum69]

Are all these numbers using api test kits?

 

[novahobbies]

The pH, KA, Ca, PO, NO2- and NO3- are API, yes. All tests are less than a year, and most are less than 6 months old. The Mag is Red Sea titration kit and less than 3 months old. All tests are well under their Exp date. Salinity is taken with a refractometer.

It's a smart guess to suspect the Potters, but these issues began deep in the coral skeleton and extended out. Not in places the angel could reach. The same can't bbe said about the Rainbow Poci: it's possible that might be Angel related, but it seems like a long stretch of coincidence that it would happen about the same time as the apparent RTN for the other corals.

 

[gatoralum69]

Reason I asked about api is I find that their tests seem to always be on the low side...I.e. If no3 api reads 0 odds are u are at 15-20. Alk reads at 10 odds are u are at 7-8. I find their tests to be a little inaccurate...but and this is a big but...if you have been using these tests all along and been getting these consistent readings then it does not matter as this is your baseline.

 

[novahobbies]

Yes, I use the same api tests as baseline.

 

[nivram]

Get your parameters back in line. As you stated the ALk seems low and see if they stabilize. A drop from 10 to 7 can cause sps to react negatively in my experience. Thats actually a pretty significant drop.

 

[marke]

Agree with others. It's an alk problem! Has happened to me a few times. Damn vacations ruin everything! Ca is ok if it drops a bit. But we can't let alk drop. Don't go tweeking to many things at once. Stay with alk issue and correct. If you don't have confidence in your test kit try salifert. Test alk more frequently than other stuff good luck !

Ps. Just for jokes! You can always try Zoas. They can withstand anything, and some like Aquaman even think they are perrty.

 

[Jeremy05]

Definitely sounds like alk. Just had the same piece die when my alk dropped to 7.