Lost many SPS. Please help identify RTN, bacterial infection or something else?

[radicaltour]

50 gal tank is 6 months old, SPS dominated.
Everything was going great then most of the SPS turned very pale 4 days ago and I've lost 10 of them since then.
sg - 1.025
cal - 450
mag - 1350
alk - 10.5 dkh
pH - 8.0
nitrate - 0 with API test kit, 10 ppm with Elos (consistently)
phosphate - 0.05 (salifert)
*No GFO, no bio pellets and no skimmer
*was carbon dosing with red sea No3Po4x (2ml per day)
*2 kessil LEDs sitting 6 inches above water running at 30% intensity

This issue occurred right after two things:
(1) completely replaced white sand with BRS Hawaiian black aragonite sand
(2) dumped 500ml of RO/DI + washing soda (A&H sodium carbonate) into tank to increase pH

Based on the pictures, the coral tissues are breaking off.
Please help me figure out what the issue is and how I may stop the bleeding.

Thank you all.
-Dave

 

[aaron23]

Can we see some tank photos? Tank is very new. How many fish do you have? What are your tank specs lighting etc

 

[Rick.45cal]

How much did your alkalinity increase when you added 500ml of sodium bicarbonate?

 

[spidercrab]

Yea soda ash will kill them in a flash if not dosed slowly.

 

[spidercrab]

Rule of thumb never chase pH with supplements.

 

[Triggreef]

Most likely that bump in ph/alk. Definitely not nutrients. Rtn is tough sometimes there's no stopping it. However I've had really bad frags heal up and come back within days of being moved to a new "known healthy" system. Key is keeping it all stable.

Imo the way that flesh is peeling is from parameter problems not pests.

 

[Diesel]

You shocked the heck out of your SPS with that 500ml.
No3 is low too and dosing your RS nopox will only make it worse, glad you stopped on that.
Not sure if your SPS are going to make it as peeling of the flesh is in almost every case unstoppable.

 

[aaron23]

You shocked the heck out of your SPS with that 500ml.
No3 is low too and dosing your RS nopox will only make it worse, glad you stopped on that.
Not sure if your SPS are going to make it as peeling of the flesh is in almost every case unstoppable.

***** lotta glue sometimes works

 

[aaron23]

Wow I totally missed that part, how much of the 500ml was the A&H? Agree with above posts that should wipe out all of your sps given the small aquarium size

 

[radicaltour]

thanks for the feedback so far!

I didn't dump the 500ml in at once. I mixed a gallon of RODI water with two teaspoons of sodium carbonate then poured 250ml into the tank then another 250ml a few hours later.
The pH went from 7.9 to 8.05

Here's the kicker. The pH chasing was 5 days ago. I've added a few frags just 3 days ago and they are dying too. I wouldn't think they would be affected by both the substrate change and the soda ash incidents.

 

[radicaltour]

I have 4 small fish and 1 medium-sized diamond goby.
I feed them once a day with frozen mysis/brine.
Then I pour 10ml of phytoplankton/phytofeast/marine snow into the tank at night.

Forgot to mention I'm currently dosing the KZ Color system (1-2-3-4).
I also run carbon with chemipure.

As stated above, i don't have a sump. I stopped running GFO, skimmer and biopellet a couple of months ago.
Phosphate and Nitrate have been stable.
Alk, Ca and Mag have been stable thanks to a continuous water change (1 gallon every day).

 

[aaron23]

thanks for the feedback so far!

I didn't dump the 500ml in at once. I mixed a gallon of RODI water with two teaspoons of sodium carbonate then poured 250ml into the tank then another 250ml a few hours later.
The pH went from 7.9 to 8.05

Here's the kicker. The pH chasing was 5 days ago. I've added a few frags just 3 days ago and they are dying too. I wouldn't think they would be affected by both the substrate change and the soda ash incidents.

That's exactly how I read your initial post. Did you measure the alkalinity at all after the both doses?

 

[Diesel]

@radicaltour
Something went completely wrong and looking at the info you gave us it must have been something that you dosed in your tank.
250ml is still a lot for a 55 gallon tank.
Some ppl dosing just 150 ml in a 200 gallon tank spread out over 24 by hourly dosing and they have large colonies, oh and a sump.
Water volume ads to the balance of your tank, and long term success.
IMO either you made a error in your PH reading and in reality it was a lot more than just 8.03 or you batch of mix was bad, maybe in conjunction with the Nopox it set off a reaction in your tank.
But pealing of skin from the Acro's is simple a rapid water quality change.

 

[radicaltour]

unfortunately, I did not measure the effect on alkalinity that day.
However, i do measure alk every day for the past couple of months.
So as I recalled, alk was at 10.2 dkh before the soda ash dose.
The day after it was sitting at 11 dkh.

 

[Brew12]

I can tell you I dosed some 2 part to quickly and raised my alk by 1.3dkh in one shot. It was enough to bleach one sps in 24 hours and other 24 hours after that. I had a 3rd that showed some bleaching but it stabilized. Was amazed at how quickly what I thought was a relatively small change could do damage.

 

[radicaltour]

@radicaltour
Something went completely wrong and looking at the info you gave us it must have been something that you dosed in your tank.
250ml is still a lot for a 55 gallon tank.
Some ppl dosing just 150 ml in a 200 gallon tank spread out over 24 by hourly dosing and they have large colonies, oh and a sump.
Water volume ads to the balance of your tank, and long term success.
IMO either you made a error in your PH reading and in reality it was a lot more than just 8.03 or you batch of mix was bad, maybe in conjunction with the Nopox it set off a reaction in your tank.
But pealing of skin from the Acro's is simple a rapid water quality change.

I totally agree I did something bad 5 days ago to cause this train reaction. But i'm curious about why new frags just added 3 days ago would suffer the pH imbalance?
Fyi, I get the pH values from API test kit and from a vertex pH probe (via the vertex cerebra controller).

I've done a 40% water change in the past couple of days but that hasn't helped.

 

[Brew12]

I totally agree I did something bad 5 days ago to cause this train reaction. But i'm curious about why new frags just added 3 days ago would suffer the pH imbalance?
Fyi, I get the pH values from API test kit and from a vertex pH probe (via the vertex cerebra controller).

I've done a 40% water change in the past couple of days but that hasn't helped.

Did you do the 40% change after the new frags were added to the system? That may have been a new, separate shock that could have impacted them.

 

[aaron23]

2 teaspoons can be the factor like diesel and brew are saying. My suggestion now is since the tank went through some dieoff I would run some carbon for a few weeks do a bigger water change and see what happens next

Also the pH imbalance isn't what is causing the rtn. My pH swings from 8.1-8.5 every 24 hours

 

[aaron23]

Actually here you go, 2 teaspoons brings up your dkh from 10-12

 

[radicaltour]

Did you do the 40% change after the new frags were added to the system? That may have been a new, separate shock that could have impacted them.

I did the 40% water change in a total of 3 days (after the new frags were introduced). So yes, this could have shocked them. But does this usually lead to tissue/flesh peeling though?