STN from hell, please help

[DanTheReefer]

Remember that corals have a delayed response to stress. You mentioned many things that happened in addition to the initial crash of nitrates.

Large water changes – drastically shifts tank parameters and depletes DOC and nutrients
Use of ROX – Aggressive use can strip DOC and trace elements
Changes in alkalinity
Sudden changes in Phosphate from 0.350 to something lower
Sudden changes in Nitrate from 0 to 10ppm
Dosing antibiotics

Each change individually is capable of inducing STN / RTN.

In my opinion, the most important thing to do is to stabilize the parameters, and wait it out. Unfortunately the situation is likely to get worse before it gets better.

When I have an issue with SPS, I like to reset my parameters to my normal parameter setpoints, and go into what I call “Save Mode” with the following checklist:

4 to 5 20% water changes over a few days
Alk to 7.5
Nitrate to 5 ppm
Phosphate to 0.050 ppm
No GAC
No GFO
No UV
Reduce lighting to <300 PAR
Verify good 100x flow
Verify salt SG to 34-35 ppt
Verify temperature 79.5
ICP test
Verify no pests
Dose Acropower if corals appear to be starved
Dose vinegar 18 mL/100 gal if corals appear to be starved
If RTN, then frag off healthy tissue
Test, test, test, and keep everything rock stable
Continue moderate water changes as necessary

Your setpoints will likely be different, but you get the idea.

This video explains some thoughts about the complexity of bacterial infections in corals.

Thank you for sharing, fascinating

 

[jeffyang]

I think you will be better off without adding anything to your tank at this point. Just keep the basic parameters stable and wait out.

 

[mhaley98]

I don’t believe there are any studies done to support your statement.
Especially I do not believe there is any scientific study that shows coral holobiont is not impacted by antibiotics. But if there are I would like to read them.

What one can say that so far the R2R experiments shows no ill effects. But corals do depend on bacteria and I am sure overuse or continuous use will lead to negative impacts. This is hobbyist playing with fire.

Also overuse, improper use will lead to antimicrobial resistance and that will be very unfortunate.

I agree. All antibiotics, like with humans, will kill both good and bad bacteria. The way that antibiotics work is that they target specific components of the bacterial cell wall and break them down to essentially make the cell wall explode. The antibiotic doesn't know what a good or bad bacteria is, and will kill all bacteria with that specific component regardless of the bacteria is beneficial or harmful in nature. There are different types of antibiotics that will kill different types of bacteria, because they target different characteristics/components of the cell walls that not all bacteria have.
This is exactly like what happens in the human body. Often when people take antibiotics to get rid of one bad strain of bacteria, the good ones die off as well, and then what can happen is opportunistic organisms, such as yeast, overgrow and create new problems.
I would be extremely cautious of using any antibiotics in a reef tank unless it is a last resort, since the health of our systems, and the livelihoods of our corals, depend on the good bacteria doing their jobs. If I were to use an antibiotic, I would do what the doctors recommend with humans, and dose good bacteria after a few hours of using the antibiotic, to replenish the system with the beneficial bacteria and prevent the overgrowth of opportunistic organisms.

 

[DanTheReefer]

thanks all for the thoughts, especially enjoyed hearing Salem talk about this topic on ReefBum and with ReefBeef over the past week - thanks for the recommendation.

I dosed second round of cipro a few days ago. I have noticed some positive trends. The recession of the forrest fire digi seems to have stopped and the zoanthids near it opened up slightly for first time in about two months. Recession of large spear mint Monti also immediately haulted. Possilopora continues to STN.

Params:
Alk 9.9 dKh (was 9.7 on 5/11, stabilized)
Nitrate: 15 ppm
PO4: .91 ppm, yikes! (Was .64 ppm, think dead coral is leaching it back into water column)

 

[Pod_01]

PO4: .91 ppm, yikes! (Was .64 ppm, think dead coral is leaching it back into water column)

From my experience, dead corals or portions of it are magnet for algae. Also the dead portion will rot and pollute the water.

So these days I chop any good portion and throw out the dead and hope for the best.

Good luck,