Polyps Retracted but not Closed?

[Tangman909]

After months of success and rapid growth, my corals are now experiencing some sort of stress and closing, but only half way. The zoanthids, soft corals and LPS corals are showing the most signs of stress, but not all of them are closing. My leathers are closed completely and my SPS are not affected. This has been happening for about a week now and i am not seeing signs of it stopping. I have begun daily 5 gallon water changes on the 90 gallon tank. All parameters are normal and all fish are normal. I suspect something with water quality or maybe lighting, but my lights have not changed.
The only major mishap in the last few weeks has been a malfunction in the top off, the tank was overfilled with freshwater and dropped the salinity down to 1.020. that happened over the course of about 4 days and the corals showed no immediate signs. I am working to raise the salinity back up but I dont believe this is the problem, because it has happened before with no effects.
I have attached pictures below, please let me know any advice or experience, thanks.

https://drive.google.com/file/d/0B6eKqj4p64TZNjR6SjdTMnhUVTg/view?usp=sharing
https://drive.google.com/file/d/0B6eKqj4p64TZUnhNRENOTEphT00/view?usp=sharing
https://drive.google.com/file/d/0B6eKqj4p64TZWE1ydFpUaktiZlE/view?usp=sharing
https://drive.google.com/file/d/0B6eKqj4p64TZQ0RBbEpmUDFoaHc/view?usp=sharing
https://drive.google.com/file/d/0B6eKqj4p64TZMldxa1dnb1BKNlU/view?usp=sharing
https://drive.google.com/file/d/0B6eKqj4p64TZUjBfS080VHdHMG8/view?usp=sharing
https://drive.google.com/file/d/0B6eKqj4p64TZdUs4ZGVSenFiZmc/view?usp=sharing
https://drive.google.com/file/d/0B6eKqj4p64TZMUJyQjdWQ0Y5RUk/view?usp=sharing
https://drive.google.com/file/d/0B6eKqj4p64TZTEVfRHFTOExpRU0/view?usp=sharing

 

[markalot]

Hi Tangman,

For half closed like that the first thing I would do is think about what changed. The salinity drop might do it, change in lighting might do it, unstable params might do it.

You say params are normal which is not good enough. When salinity drops params also drop, meaning your KH may have swung too low, or too fast. Corals are not adapted to mistakes we make, like salinity changes, so the results can be random with some corals showing no adverse effects while others up and die overnight. Some might handle the first mistake and suffer in the second mistake. I like to think of it like a disease. The first goof weakened their immunity and the second got them sick.

I might dim the lighting a bit and see if things improve.

On the subject of topoffs, I switched to a timed topoff long ago and will never go back. It runs for 45 seconds every 15 minutes with no chance of a level sensor getting stuck on. I occasionally have to adjust for evaporation by either turning on an extra fan or manually adding water but changes are slow and this has worked well for me going on 2 years. It also allows me to add Kalk to the topoff and dose a consistent amount.

 

[Lsufan]

I'll start by saying that I am no expert like mark & most everyone else that posts in the sps forumn, but I've been in the hobby for a while now & consider myself successful with the accasional issue. But I wonder what your params actually are, specifically no3 & po4. Also how many fish u have & your feeding habits. It seems if it was a water quality issue your sps would be the first affected.

When I first started out with corals all I read was about having a clean tank with 0 no3 & po4. My corals were always healthy & grew but I always thought the growth & pe on my sps could be better. I tried getting my nutrients up but they always stayed 0 so I decided to start dosing no3 & things have looked better because of it. I'm not suggesting dosing no3 because I don't even know your params or if that may be your issue. But I have come to the conclusion that corals are at their best when u are adding a lot of nutrients into the tank with heavy nutrient removal. So a bunch of fish with a bunch of feedings combined with heavy nutrient export.

That has been my experience anyways, without knowing your params & more about your system it is just guessing but u may have stripped the nutrients to low for the soft coral & some lps. I would get that ato figured out also, to me three of the most important things to sps are stability, flow & nutrient import & export as long as u have sufficient lighting