A possible explanation for STN events

[Triggreef]

I do drip feed reef energy 24 hours a day

How? My understanding is that it has to be refrigerated which would make that very difficult. I'm very interested to hear about your method.

My iodine was actually high. I think it is from the red sea color program I was dosing

Interesting. I stopped using those for similar reason after a similar crash. I was also dosing lugols and didn't realize the red sea product also had iodine. I suspected iodine over dose and it was pretty high. Triton test at that time also revealed copper and zinc was high. I lost around 40 acro frags& colonies in that one. A little at a time. Moved to triton 4 part and nothing else at about the same time that happened. Much simpler.

 

[McMullen]

Great article in vibrium!

 

[Reef_Chief]

IME stn came from alk swings or flow issues most of the time. If you haven't serviced your powerheads in a while give that a try to improve their output

 

[DamianOZ]

There are obviously many things that can causes stn/rtn, so this is possibly just one of them.
I am currently going through a slight stn event in my tank. Its not the first time but its the first in awhile and it's frustrating to say the least. My tank had been doing so well as of just 6-8 weeks ago so naturally I have been desperately trying to find a cause (I have no pests, my parameters are great, etc). I'll spare you the details but I think it was a combination of things causing too much stress on my corals even though they were very healthy.
One very important thing I noticed though was a major dinoflagellate bloom. I think this was precipitated by adding a bunch of new frag plugs as well as my skimmer not working for probably a week or more while I was on vacation.

My suspicion is that the dinoflagellates are actually a lot more harmful to the tank as a whole than I originally would have thought. My thought is that they destroy the tank's micro ecosystem. Meaning, I think they kill off good bacteria, phytoplankton, and the micro clean up crew (copepods, etc). We know they can kill crustaceans such as snails and crabs because we see it happen. So why wouldn't they also kill smaller organisms? Obviously if this happens a tank crash can ensue from the destroyed ecosystem. This is what I assumed was happening and today I looked up some info on copepod biology. It turns out that dinoflagellates are well known parasites of copepods! (I know, not very scientific, but hey I'm trying) https://en.m.wikipedia.org/wiki/Copepod
But if this occurs in our tanks, there is no way for them to recover their populations since its a closed system. Unless of course we replace them.

So, my solution at the moment (now that the dino's have mostly gone away) is to reintroduce copepods, phytoplankton, and beneficial bacteria to my tank in hopes that it will restore my previous ecosystem and hopefully allow my remaining acros to recover. I'll let you know how it goes! If this turns out to be helpful then in the future repopulating the tank with these beneficial organisms at the first signs of trouble may be a good idea.

I'll put my money on the TN being cause by bacteria problems, out competing the coral for P and N.

What are you nutrient levels? your Alkalinity level and are you carbon dosing (pellets, vinegar, sugars, vitamin C, alcohol, or any of the commercial product like nopox, zeovit products, FM etc..) ?

 

[Kungpaoshizi]

My iodine was actually high. I think it is from the red sea color program I was dosing

I find their dosages for the Colors stuff to be pretty aggressive.. Makes me wonder if they need to tweak it according to certain corals and perhaps include tangents about NOT changing water.. I still only use a drop or two a week even though according to their instructions I would need a ml or so iirc.