RTN on SPS!

[ca1ore]

Hard to see anything materially amiss. Always a nail biter when making changes to established SPS colonies. Probably a combination of alk and nitrate swings.

 

[Tautog]

Changing your sump and giving your DT a larger sump shouldn’t change anything, only good things.
Did you test your new water? Aerate it before using?
I recently caused a crash with a high Alkalinity in fresh mixed water for a WC. I didn’t add much salt to the mix, trying to be perfect at 1.026, but unfortunately the KH was over 13 dKH. Yep, 2 cups of salt, even in 45 gal of H2O, makes a big jump in Alkalinity. I’m still recovering, still removing dead corals, still devastated. And it still sucks that I figured out what happened. High nitrates and phosphates didn’t matter with high Alkalinity, but I believe the spike just pushed them from no return. I have stopped STN/RTN, but not this time. Chalices and softies are fine, thriving.

 

[Aquavaj]

If it was a DIY sump did you let the silicone fully cure first? And you used aquarium safe silicone?

 

[ca1ore]

That’s a good point. Silicone with mythical mold additives is not the problem; insufficient cure time is. I always give it at least a week.

 

[EMeyer]

Other people have different experiences, but in my tanks I've never had an SPS that could survive Alk above 8 for very long. Not sure what the high alk tanks are doing different but if alk is above 8 I would address that before anything else.

 

[zack801]

Obviously a typo ....

Obviously