Soft Corals Dying/SPS Appear Fine

[Eric45]

So that's the problem. All standard parameters seem fine and no algae problem so I doubt its organics. Also, I've seen no visible critters although that may still prove to be the problem.

I'm wondering whether it is some form of chemical deficiency. Alk/Calc/Mg are fine and I dose nothing else. The tank has been stable for a long time and this is a recent event. My first loss was an anemone I'd had for years; it just shrunk up and disappeared. Now my scolemia, acans, and hammer are all bleaching out from the outer margins. The SPS seem fine and are continuing to grow as are the xenia, favids and gonio's.

Could it be iodine or potassium? The lighting is a maxspect 400 w set on a max of 60% for a couple of hours and declining from there. No radical changes in lighting over the past few months -- small ones though.

That's all I can think of. Any thoughts, speculation or even wild guesses would be appreciated! Maybe its old tank syndrome, the system is about a decade old.

 

[Dkuhlmann]

Your water is probably too clean to keep softies if they are doing poorly and your SPS are doing well. I would shoot for maintaining a nitrate level of around 5, at this your SPS still will be fine and you'll be able to keep all 3 coral types.

 

[Reef Frog]

You mentioned scoly, acans & hammer bleaching. For me, these are all low light corals that I've had to be careful of having too much light, even with my T5 fixture. Since you've been slowly increasing your lights, Occum's Razor suggests this could be the cause. Maybe move them to more shaded areas if you think you must maintain the current intensity for some reason. Or just move back to the lower settings. BTW how long have you had the LED fixtures & how long did it take for the nem & LPS to start ailing?

Another possibility could be some element building up over time. Perhaps something has been slipping by your RODI for a long time and concentrating in the water. Or perhaps something from your salt is concentrating. Maybe change out your RODI filters & resin and start a program of more significant water changes. Possibly use that opportunity to remove any large amounts of old detrius that might have accumulated over the last decade. Certain undesirable biological compounds could be building up.

I would also target feed the ailing corals. If you think you're stripping the water, maybe back off on GFO for a while and see if a dose of amino acids perk things up. The AA may or may not help, but there isn't a whole lot of downside except maybe a little bit of Cyano.

Finally, look to the small often overlooked stuff. Is temperature swinging? Calibrated refractometer? Have you checked for parasites at night? Has flow changed?

Well, you said some speculation was OK and you got some! Best wishes, I hope you get this solved.

 

[Eric45]

Thanks for the suggestions. I've considered that the water may not have enough NO3, but I stopped vodka dosing a while back so my nitrates are probably detectible. I did see what looked like a couple of bristle worms around a Duncan, but none around any of the other corals and I doubt it was any kind of parasite that wiped out the anemone.
Lighting could be an issue and I have move a few corals out of the direct light, but if it is the cause, its probably too late. I've been running the Maxspect for about 9 months or so. I do target feed the corals about once a week and for the heck of it changed the salt from IO which I've been using for about a year to Tropic Marin. It hasn't seemed to make a difference. Temp is fine but a good thought. I may try the amino acids as I really think its a chemical imbalance or some supplement I should be using.