I like a challenge but even this has me perplexed :rollface:

P

PhantomCavie

New member
Alright so here is the story. Tank is a 40 breeder with a 20 gal sum/refugium (running chaeto). I have 2 Skimmers, both reef octopus, a 90 HOB and an insump 152-S, (total rated to ~ 240 gal skimming). Stock of tank is a mixed zoas, LPS, SPS, softies, you name it, 5 fish (2" occellaris, 4" midas blenny, 2.5" pygmy angel, 3" leopard wrasse, banded shrimp goby). Using GHL to monitor pH and dose Alk and Ca (B-ionic 2 part, in equal parts). Using 4 stage RO/Di for ATO, TDS= 0). 24" reef breeder photon for light (2 channels, maxing out at 50 for an hour each day).

Tank has been up and running since 2014.

Parameters, using Red Sea tests:
Ca: ~465ppm
Dkh: ~8
Mag: ~1420
Salinity: ~1.026
Nitrates: 10-15ppm
PO4: <.08ppm
Temp: 79 F
pH: ~8.2 daytime --- ~8 night time (stable for at least 6 months according to GHL probe)

Now for the fun part. For the past 3-4 months my SPS have been undergoing STN and occasionally RTN. However, my two trumpet coral (one neon green, one blueish) have also receded almost completely (each with 10+ heads that I've had since the tank finished cycling). That being said the zoas and other LPS are flourishing, as well as some forest fire digi and motipora. The SPS that have lost flesh have been a large birds of paradise birds nest, acros, and a setosa.

At first I thought it would be nitrates causing the problem, but my tank has always sat around 10-15ppm even when I was getting steady growth on the sps (I have logs dating back to 2015 at least once a week). Also, I have a large amount of coraline algae continuing to appear, which, if memory serves, is an indicator of good tank health.

So that is about the gist of it. Other than salinity being a hair high I'm flummoxed. Any thoughts?
 
Also, I am still getting growth with the montipora and digi, (the montipora is about 10" across), why do my magnesium levels never drop? I don't dose mag and my last water change was over 2 months ago (when my parameters are in check I don't tend to do them as often).
 
My tanks never consumed enough magnesium that I needed to dose it for that reason. Water changes were more than enough to keep the level up. That's fairly common, from what I can tell.

I am not sure what is happening to your SPS corals. Coralline is a lot less picky than SPS, as far as I can tell, so I wouldn't count on it as a good indicator. Some possibilities would be coral warfare, or chemical warfare of some type, or perhaps some sort of other organic in the water that is causing problems for some of the corals. I might start by running some fresh GAC and upping the water change frequency. Stopping the feeding for a couple of week might be interesting, as well.

I wish I could say that I am confident that this problem can be resolved easily, or at all, but we see a wide range of results.
 
bertoni said:
Some possibilities would be coral warfare, or chemical warfare of some type, or perhaps some sort of other organic in the water that is causing problems for some of the corals. I might start by running some fresh GAC and upping the water change frequency.
Click to expand...

Since you have softies in the tank that could very well be it. +1 on running some carbon. Softies are notorious for releasing toxins in the water.
 
Nope, I don't know of much in the way of proof of much of anything with regards to organics in our systems. That's one of the problems of diagnosing and handling problems like this. Some research might turn up some papers on the structure of such toxins, at least for a few species.
 
This has been an issue for me for the past few months as well. Everything growing and all parameters very close to yours. Suddenly SPS started to recede. Some top down, others bottom up. Best I can gather is being a mixed reef it got to a point where something became unhappy and started to irritate the others. Of course the SPS and a few trumpets took the worst of it.

I've upped the water changes which seems to have slowed the recession. Still every couple of days I witness more STN/RTN on what few SPS frags I have left.

Best of luck.
 
Are you sure you are not describing my tank? :-(

I have been having the same problem lately with RTN and STN in my mixed tank.

My parameters are as follows:

Salinity = 34 ppt
Ph = 7.80-8.20
Alkalinity = 8.3 - 8.6
Calcium = 420-430
Magn (Mg) = 1230-1260
 
For these mystery problems I think sending out a sample for more comprehensive analysis (i.e. the triton ICP testing) might be wise and give visibility into other metals/praramters etc..

I have been there and know the frustration.
 
I'm not sure that the Triton methodology is accurate enough to find problems reliably. There have been various limitations documented.
 
HBtank said:
For these mystery problems I think sending out a sample for more comprehensive analysis (i.e. the triton ICP testing) might be wise and give visibility into other metals/praramters etc..

I have been there and know the frustration.
Click to expand...

Funny that you mentioned it. I had somebody here to check it yesterday and he convinced me to send samples to Triton. Triton is big in Europe. Reading about the limitations of Triton, I was little hesitant, but figured what could I lose.

When I get the results, I will judge what to do with them. Maybe I can post it here to discuss.
 
jjencek said:
Funny that you mentioned it. I had somebody here to check it yesterday and he convinced me to send samples to Triton. Triton is big in Europe. Reading about the limitations of Triton, I was little hesitant, but figured what could I lose.

When I get the results, I will judge what to do with them. Maybe I can post it here to discuss.
Click to expand...

Would be interested to find out results and get opinions.
 
Here's my 2 cents: Correct me if I'm wrong but your corals have been growing but your fish population has been fairly stable. You're feeding regimen for both fish and corals has also been fairly stable.

We know some corals are more likely to feed heterotrophicly, they prefer organic particulates and organic N & P. Some are more likely to feed autotrophicly, they prefer inorganic N & P. But we don't really know what most corals prefer. (Here's a paper looking at this, unfortunately it looks at a very limited number of species http://www.academia.edu/1647139/Coral_farming_effects_of_light_water_motion_and_artificial_foods )

So one hypothesis is as the corals have been growing the amounts of nutrients, organic and inorganic, have stayed the same. The levels of inorganic N & P have are high enough to satisfy the corals the prefer inorganic N & P as they grow. But the corals that prefer organic N & P have not been getting enough and are starving.
We can't test for organic nitrogen or organic phosphate but maybe trying foods for corals might help.

Another problem is what's happening with TOC/DOC building up in your system. Feldman, et al, did a study and skimmers had minimal effect on preventing TOC from building up over a 30 day period. Water changes are far more effective. How TOC/DOC compounds influence the microbial processes in our aquaria is sadly beyond our ability to test but some types of DOC promote pathogenic bacteria. We also know Wright, et al, found the immune response to pathogens varies greatly between the different genotypes with in a single species so we should expect very different responses between species (and the terms LPS and SPS have no relevance in determining it) https://www.nature.com/articles/s41598-017-02685-1
 
bertoni said:
I'm not sure that the Triton methodology is accurate enough to find problems reliably. There have been various limitations documented.
Click to expand...

Better than sitting there with nothing and frantically trying everything you can to stop it IMO, speaking from experience when you feel like you have exhausted the obvious.
 
bertoni said:
Is it? If the results are wrong, what does running down blind alleys accomplish?
Click to expand...

Doesn't hurt since you are already going down blind alleys... again, this is the context of having no other options, i.e. "a mystery".

People are capable of looking at the results while also considering there may be some error. I like analytical data, but then that is what I do for a living.
 
I don't understand how incorrect information is supposed to help. You can generate incorrect information on your own, without paying Triton.
 
Well this got off topic....

Hopefully when the OP gets back results we can resume getting to the bottom of this. Appears lots of hobbyists experience this so it would be nice to know if something is missing or something has been introduced as the cause.
 
Hey, OP here. Did water tests again today with almost identical levels. So no answers there. The thought about TOC/DOC is interesting though. However, if that is the case, why are some people able to cut out water changes entirely and not suffer similar effects?

Also, has anyone heard anything about the possibility of corals outcompeting other corals for nutrients as they grow in size? Given that I have several types of large SPS that are still growing will, could this be a possibility? Zoas, blastos, and softies seem uneffected, even my leptos are doing fine.
 
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