Corals RTN overnight, just when I thought things were going well

Latte · Mar 28, 2022

Hey all, on Sunday I did approximately a 40% water change (red sea max nano) with a new bucket of salt (Aquaforest reef salt, the same I was using before).

Before then everything was going really well, aside from a Dino outbreak that I'd just started to see some progress with. I was seeing some good growth with my acro frags and was super happy.

Woke up on Monday to see my skimmer was producing a lot of microbubbles which was weird, and a lot of the corals looked unhappy, I assumed from the micro bubbles. I cleaned out the skimmer, fed heavily, micro bubbles continued so I turned off the skimmer overnight.

Woke up today and two of my acro frags are completely white, my goni is dead, my torch has still extended but weirdly deflated/flat polyps and showing a lot of skeleton. Some others look ok but nothing is flourishing. Pretty devastated really.

I did some tests.

Alk: 7.6 (Hanna)
Calcium: 400 (red sea)
Phosphate: 0.01 (I've been trying to keep this a bit higher, was 0.04 two weeks ago) (Hanna)
Nitrate: 5 (red sea)
Magnesium: 1650+ (extrapolated by adding extra titration, reading stops at 1500) (aquaforrest)

My magnesium has been on the higher side, usually 1450 to 1500 for a while without dosing.

I checked my salt water bucket and magnesium was even higher than in the tank. Though I understand I'm just using a hobby kit and it could be inaccurate, I don't want to just blame aquaforrest salt but I can't see what else it could be?

Would love some help or suggestions, my first experience killing corals and I feel guilty and heartbroken as it took out a couple of my favourites.

Latte · Mar 28, 2022

To clarify, the variables are all mostly the same as tests two weeks ago except for the magnesium which jumped about 150.

jcolliii · Mar 28, 2022

Sorry to hear about your losses. Only change was the new bucket of salt? Any new additives? PO4 is too low for my liking, but lots of people keep sps with low PO4 - mine really dislike that though. How big a dino outbreak? Did you use any chemical weapons on them? It can get warm down your way... did the tank get really warm recently?

Latte · Mar 28, 2022

jcolliii said:
Sorry to hear about your losses. Only change was the new bucket of salt? Any new additives? PO4 is too low for my liking, but lots of people keep sps with low PO4 - mine really dislike that though. How big a dino outbreak? Did you use any chemical weapons on them? It can get warm down your way... did the tank get really warm recently?

Dino's outbreak was very bad, but it looks like it's on the decline and hasn't been as bad over the period the corals started dying. Temperature is stable with a couple degrees, I have a seneye on the tank which would let me know if something went wrong heat wise and allows me to check back on readings.

I didn't use any chemical weapons on Dino's, just feeding heavily, some reef roids and aminos ocassionally.

Maybe two or three weeks ago I started dosing components 123 from AF again. Was previously just doing alk as my calc got too high I have since stopped dosing magnesium as it's clearly too high.

Right up until the water change though the colonies I have had RTN were full PE, great colour. Water change and less than 48 hours later, all white skeletons.

Latte · Mar 28, 2022

Going to get an ICP done I guess, at a complete loss at the moment. Not sure how to fix anything as it seems it was a water change that brought it on, but sitting back and watching all my corals die isn't exactly a great course of action either

gbroadbridge · Mar 28, 2022

Latte said:
Going to get an ICP done I guess, at a complete loss at the moment. Not sure how to fix anything as it seems it was a water change that brought it on, but sitting back and watching all my corals die isn't exactly a great course of action either

How long ago was the previous water change? And how big is the tank?

Latte · Mar 28, 2022

Previous water change was two weeks ago, tank is 20g AIO. I usually do water change weekly but I missed a week as I was busy so I did a slightly bigger water change this week to make up for it, seems that may have been the issue. Not really sure

gbroadbridge said:
How long ago was the previous water change? And how big is the tank?

TheHunterYall · Mar 28, 2022

Salinity issue? 40% is a big one.

Brian_68 · Mar 28, 2022

TheHunterYall said:
Salinity issue? 40% is a big one.

I agree, 40% is huge all at once for acros.

Latte · Mar 28, 2022

TheHunterYall said:
Salinity issue? 40% is a big one.

Brian_68 said:
I agree, 40% is huge all at once for acros.

Salinity is the same, possible it's just too big a water change. I sent off an ICP, the fact it's killed my goni, torch and now a Monti too makes me think there's likely something else going on? Not sure. Fish and CUC all seem fine.