Sudden tissue loss / bleaching, unsure why

[cdw79]

Parameters:
Phosphate .06 (Hanna)
Nitrate ~8 ppm (Salifert, looked slightly less than the pink for 10 ppm)
Calcium 455 (Apex)
Magnesium 1320 (Apex)
Alkalinity 9.45 (Apex)
Temp approx 77-78 degrees (Apex)
Tank has been running for ~6 months with no issues or coral loss up until now, bar one stylocenellia frag I got way too early after my tank's cycling several months ago.

In the past week and a half or so I've experienced my blue Stylo frags, which had been in the tank for about a month and doing great, all of a sudden each have their tissue recede from the base upwards. At first it compounded very quickly, but the past 4-5 days I've not noticed it worsening.

In the past 3 or 4 days, I noticed this chalice developing a white spot on the edge, and I've noticed it slowly starting to move along the rim. This actually happened when I first got it about 3 1/2 months ago (probably too early for my tank at the time) but came back quickly and has grown since with no issues.

Today I've noticed parts of my forest fire Digi with polyps not as extended as usual (this could very well be because of my hawkfish, I've definitely seen him perch on those mini colonies a few times), but the trend isn't great all things considered. The only thing I can think of is a lighting issue- I had been raising my Hydra 32's 3% or so per week per the advice of a seller I'd gotten a gold torch from, but I saw another torch displaying early signs of bleaching, so I put the intensity back down to about 75% (where it was to begin with) and placed the torch on the sand bed.

Maybe the decrease in light (maybe a month ago now?) was part of the issue? I know nitrates are somewhat higher than they should be but they've been that way for awhile now so it would seem weird to me to all of a sudden be a problem. This has been totally stumping me, so any help would be great! Going to go do a water change for good measure in the meantime. Thanks

 

[cdw79]

Pictures for reference, albeit less than ideal quality

 

[PokeFish]

do you have something eating the coral

 

[Lavey29]

What are your par numbers? What flow are you using? Have you done an ICP to check trace elements? 6 months is a pretty young tank for SPS so I can forsee problems there until the tank matures.

 

[cdw79]

Nothing that I'm aware of is eating any coral. The stock list is

2 ocellaris clowns
Yellow Assessor
Leopard Wrasse
Pearly Jawfish
Tiny Biota mandarin
Bangaii Cardinal
Longnose Hawk

I planned the livestock to not be a danger to coral at all (as much as I like angelfish, lol) so no issues there. As far as pests, I dip all corals before they enter the tank so I'd be pretty confident it's not a pest issue, as far as I'm aware at least

 

[cdw79]

What are your par numbers? What flow are you using? Have you done an ICP to check trace elements? 6 months is a pretty young tank for SPS so I can forsee problems there until the tank matures.

That was actually the only other thing I was thinking about. I haven't tested PAR as I haven't been able to get my hands on a PAR meter with covid and all. For what it's worth, the Hydras are about a foot above the water surface, and the corals in question are about 10 inches and 16 inches beneath the surface, respectively.

I've never done an ICP test, as I'd like to think that between the 5 major tests above I'd have my bases covered. The point about it being a new tank is definitely fair, I just don't see what the problem actually would be given the parameters. My regents are almost out for the Apex so I'm going to do a replacement and recalibration (maybe the readings are off somehow?) but I'm anxious to bump up the light thinking it might exacerbate things, not really sure

 

[damsels are not mean]

I've never done an ICP test, as I'd like to think that between the 5 major tests above I'd have my bases covered. The point about it being a new tank is definitely fair, I just don't see what the problem actually would be given the parameters. My regents are almost out for the Apex so I'm going to do a replacement and recalibration (maybe the readings are off somehow?) but I'm anxious to bump up the light thinking it might exacerbate things, not really sure

Could be some metal leaching into the water. ICP test could confirm this. That's the real reason for an ICP test IMO.

TBH sometimes STN at the base just happens. It's not something obvious all the time and I've heard of plenty of nice looking old tanks getting small amounts of STN seasonally or randomly. Remember that we ask the unnatural when we expect our corals to always look perfect. Wild reefs are pretty ugly when you zoom in...

I love that your first thought is "get ready for a water change". Big water changes instantly (albeit temporarily) solve all water chemistry issues periodt.

 

[cdw79]

What would case that do you think? I've heard of electricity getting into the water but not metal, can't think of how it could happen (obviously no copper treatments have gotten in, fo example, since I haven't had to use any yet). I also checked my RODO water awhile back and it came back with 0 TDS, though I don't know that that would account for metals. Any ICP test you'd recommend?

If it were just those styles I'd be less concerned, but this chalice having a similar issue really put me off. Just can't understand what's happened so suddenly to cause this to happen in these two separate instances, while other similar corals are still happy seemingly- wouldn't metal leaching affect everything more or less?

 

[damsels are not mean]

What would case that do you think? I've heard of electricity getting into the water but not metal, can't think of how it could happen (obviously no copper treatments have gotten in, fo example, since I haven't had to use any yet). I also checked my RODO water awhile back and it came back with 0 TDS, though I don't know that that would account for metals. Any ICP test you'd recommend?

If it were just those styles I'd be less concerned, but this chalice having a similar issue really put me off. Just can't understand what's happened so suddenly to cause this to happen in these two separate instances, while other similar corals are still happy seemingly- wouldn't metal leaching affect everything more or less?

metal can leach from a lot of places. Damaged pumps, magnets, screws lids and lighting fixtures, etc. You would be surprised. There is some filter media called Marine Pure that has a tendency to leach aluminum for example.

 

[cdw79]

After waiting for almost a week, I've finally gotten my ATI test back. Any thoughts? Unclear if these issues they noted are significant to have caused the above issues..

Also, any recommendations for how to solve these issues (both short and longterm) that would be great. Thanks

 

[sculpin01]

Your salinity is very low for keeping corals. You’re at 28-29 when the standard is 34-36. I’d work on that first. Also, probably drop your alkalinity down to 7 in the interim, given your phosphate is 0.02.

 

[cdw79]

I noticed the salinity too- in the past day and a half I have been slowly raising it and I'm back up to about 1.025, so that's one thing crossed off the list. interesting about the alkalinity, will look into lowering it (slowly, though, as I know quick swings can make things worse). But are those two measurements likely to be the source of the issue?

 

[sculpin01]

Alkalinity is closely entwined with nutrient levels. High nutrient levels tolerate high alkalinity much better, while low nutrient levels (as with your tank) typically require alkalinity to be in the 6-8 range (e.g. the zeovit method). Phosphate levels appear to be more critical than nitrate, but both can cause problems. Very established tanks with high fish loads can sometimes bypass this rule, but it's not 100%.

(PDF) Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates

PDF | Enrichment of reef environments with dissolved inorganic nutrients is considered a major threat to the survival of corals living in symbiosis with... | Find, read and cite all the research you need on ResearchGate

www.researchgate.net

 

[Viva'sReef]

Your Salinity would be my guess.

 

[BrianAnthony]

I vote... Not your lights right now.
Something happened... a while ago. Not enough light takes a long time. Would focus on parameter stability.

 

[Biologic]

OP, definitely get that salinity probe on your apex. It’s worth it. It works perfectly when you don’t obsess over it for the first week or so. Don’t let the threads here that poopoo that probe.

Also salinity with a refractometer is the first thing you check before all other parameters. It’s the fastest, cheapest, and remember it nearly determines all other parameters.

 

[cdw79]

I'll definitely look into that salinity probe- I'd always thought it seemed a little useless because in theory the ATO would keep things level, but clearly that's not necessarily the case. I think for now I'll just take the extra few minutes out of the day and just give it a quick check every couple days so I don't get to this point in the future.

But like you guys mentioned, after going through almost everything imaginable, my LFS and I came down to either lighting (seems less than likely), my several leather corals' chemical warfare (I haven't run carbon up until now) or an alkalinity change that was too quick (I didn't see the point of a All at 11 so let it drop down to 9 or so).

As far as alkalinity levels go, what is a "reasonable" variance? Maybe .25 either way? It's been harder than I expected to keep it exactly stable despite having the apex testing and dosing for it