Sudden Tissue Recession...why

[treehugger]

So I'm running a 275g total volume system. It's a mixed reef (heavier on the LPS end)
Lighting: 2x250w MH (2x14k 1x20k radium), 2x96w power compacts, 4x23w t5Halides 6 hrs a day, compacts & t5 6hrs
temp: 78-82 (no chiller yet)
sg 1.026
P & N : <5ppm
Ca: 450
Mg: 1300-1400
Alk: currently 11dkh (had a spike when I cleaned out my Ca Rx up to 13dkh ~1 week ago)
ph: ~8.0-8.2 daily swing
They only thing I've been doing different is that I just started adding kalkwasser to my makeup water about 1-1.5 weeks ago
Today I noticed that two of my torts (Cali and Oregon) and 1 millie have some tissue recession at their bases on the frag plugs. They all still have great polyp extension and seem otherwise happy. None of the other sps seem to have any issues...yet. Could adding the kalkwasser be causing this at all? Or the spike in Alk? I was thinking maybe the kalkwasser was swinging the pH to much when it was added. Any thoughts would be welcome. Thanks in advance
Jeff

 

[Herefishyfishy]

My PH has regularly swung from as low as 7.9 to as high as 8.5 but typically from night to day is about .3 delta. The alk might have spiked, I have had STN from that before.

Temp swings can stress them a bit too. Enough food in the water?

 

[treehugger]

I've been feeding pretty regularly (been slacking a bit with the move though). I thought maybe the Alk thing might have stressed them a bit. I'm sure a nice water change is in order I just don't have any made up...

 

[tamarindthai]

i do,,come and get it already mixed about 40 gals,,give me a call ,,jeff

 

[gary shandling]

PH will tend to swing due to daily tank activitys. This tends to level out as tank matures and water levels stay steady. For PH test in the morning around the same time for most accurate readings.

Bleaching or tissue reduction around the edges usually means low food source and it will continue to receed untill it meets its food source.

2 sources would be the food type and feeding scedule. And amount of flow .

 

[kevinpo]

Hello Jeff,
Most likely the cause is the sudden spike in alkalinity. Even 11dKH (3.92 meq/L) is rather high IMO. 8-9dKH (2.86-3.20 meq/L) is what I run my tanks at. NSW is 7-8dKH (2.51-2.86meq/L) but most people run their tanks a bit higher which helps compensate for the higher bio-loads found in home aquariums.

82F is a little on the high side but I don't get too worried until 83F. I turn off a halide or two at 83F.

Regards,
Kevin

 

[treehugger]

Thanks for all the responses. I figured the spike in alk was most likely a big part. Also when the alk spiked so did my Mg and Ca. It's sounding like maybe I gave them a bit of a burn when my Ca RX went nuts. Hopefully a couple h2o changes and getting things back in check will get these sps back on track. Thanks everyone.

 

[Jan]

I second the alk swing as the cause of the TN at the base. Either too low of alk, or alk swings has caused that in my system.

 

[treehugger]

well it definately wasn't from having the alk on the low side