I really doubt its iodine.. Can you post your alk cal phos and nitrate levels? Also are you running carbon? SPS and leathers seem to not mix well together in smaller tanks. What kind of lps is doing good?
Corals Doing Poorly:
1. Red Monti Cap
5. Kenya Tree
6. Pink and gold palys (not growing and are small but seem to be doing okay)
7. GSP almost never opens, beginning to grow algae on it.
8. Blue mushroom (I think this was stung by my duncan though so likely unrelated to this issue).
I'm using ESV salt mix, changing 5 gallons weekly on a 20 gal tank 10 gal sump.
I'm thinking that you are starving the corals. Do you feed the corals at all? Also 5 gallons a week on a 20 gallon is a lot and can spike the alk and cal. I would shoot for 2.5 gallons a week but this is just a guess without knowing test results.
Thanks for the feedback. I'd been doing the five gallon changes for about five years (mostly in a different tank) without issue. I'm putting mysis and marine snow into the tank as food for the corals but if it was starvation wouldn't lps be suffering as well?
I've not added any strontium. Iodine was my first attempt. As for placement I don't believe so. I have three leather frags same leather all in different locations in my tank some high some on the sand. Some dead center others on the edges of the tank. All of which look the same bleached white.
Hello, reefs.com, this is my first post! I saw the topic and thought I could weigh in since I had something similar happen to me recently.
Have you considered that your soft corals may have started emitting toxins into the water that is irritating your corals? This is a self defence mechanism that most (or all??) soft corals have, I believe. I too have kenya trees and some other softies mixed in with my LPS, but I don't have any SPS. One day I noticed that all of my corals were suddenly irritated by something, and most of them were all sucked in completely for a few days. After testing and retesting I found nothing wrong, so I decided to move my kenya trees and toadstools to another tank, since I read that these can be the most likely to emit toxins. I also replaced my carbon and did a big (30%) water change. I did another water change 2 days later. After about another day my corals perked up and things were be back to normal. I too noticed that my LPS (trumpet corals and frogspawn) were the least affected by whatever was in my water. This still doesn't prove that it was my soft corals emitting toxins, it could have been a total coincidence, but its something you could look into. I had recently fragged my toad stools, and had moved some corals around, which could have triggered this defense mechanism, who knows.