recent trend of stn

[cilyjr]

i had a tank crash a while back and have decided recently to bring the tank back ti its former glory. in doing so i have gotten some new corals a mixture of sps and lps coral. and over the past few months some of the more demanding sps corals have started to stn. its kind of stumping me. so i figured i would post. all the corals in question are acropora and millapora i have a stylo that is doing well as well as monti and Seriatopora

all my fish seem healthy and happy. there no animals that would eat the corals in question in the tank nor do they seem unhappy at the upper areas of growth. all seem to have good polyp extension.

some extra info ya might want
i use red sea coral pro salt and do 10% weekly changes
i run 4x ai sol blues 85%w 75%r 75%b
i recirc modded an asm g3 skimmer
flow rate is about 8500gph between the return and 4xpowerheads
i run uv, carbon (not religiously), and GFO
i use jb weld waterweld to and superglue gel to adhere corals to the rock.


tank params... tested bi weekly lately
SG 1.025
cal 430
alk 13
mag 1500
po4 .003

ro/di water 15 after ro 0 after di (87 out of the tap)

thanks for looking

[ebond009]

What are you doing to maintain levels? Any ALK or ph swings during day?

[ebond009]

ALK seems a little high.is it steady at 13 or does it swing

[FlyPenFly]

That alk is way too high for demanding SPS.

[cilyjr]

Alk is high.when I switched salts I needed to adjust kalk levels. Now its slow in coming down. High alk levels have been shown to accelerate sps coral growth however. In some ulns tanks high alk can burn tips as the skeletal structure griws faster that tissue grows. At least that is how it was explained to me. That be I ng said I am sure it is not high alk causing the trouble.
I am begining to think it may be the jb waterweld as the tricolor acro stn pattern matches the puttys contour.
Someone suggested that even the putty sold for aquarium use should not touch the tissue of coral.
Anyone else have any negative issues with the JB waterweld?

[cilyjr]

No major alk or ph swings. Alk stays a pretty consistant 13 and ang ph swings 8.10 to 8.23 or so.

[Palting]

I've used JB waterweld to anchor not just rock, but even the bare stems of SPS. One of the SPS that was anchored this way is a millepora. Over time, the millepora has encrusted and overgrown the putty. So, no, your problem is not from the jb waterweld.

I have to agree with the others. The 13dKH alk is too high. Max alk should be 11dKH, beyond that you have problems. I have my alk at 8, and I have exceptional growth on my SPS coral. Whether you believe it or not, it's likely the 13dKh that is causing the STN.

Your magnesium at 1500 is on the high side as well, with 1350 max for coral.