Multiple leather types dying - not just shedding - pls help

[Spotster123]

We've been all over the web and can't find an answer to our sick Fiji leather, cabbage, plus yellow devil finger leather corals. Hoping someone might -please.

They're not just shedding, they droop, go flat, get brown algae-like coating on stalks and the fiji even has a dark grey hole in the base. We've already lost a purple sarcophyton and another purple one like the fiji leather. They seem to do fine for the first week or two after their first shed and then ultimately disintegrate. They have moderate to high flow and plenty of light. We've tried a MediCoral iodine dip twice, 5 days apart.

They also let out a cloudy liquid- is this going to hurt the other corals?

What could we try next?

Thanks for your help- Spotster123

Looks like people suggest you post details on the tank so this might seem like a lot of detail but I'm not sure what will help.

Tank Specs:
Tank: 90 gallon, live sand and 120 lbs rock, in place for 3 months, 20% water changes weekly, protein skimmer - aquaeuro, use carbon as well
Lights: MH lights 250w - 7 hours/day, actinic for dawn dusk 1.5 hrs each, blue LEDs for night
Chemistry: 0 ammonia, 0 nitrites, 20 nitrates, pH 8.4, salinity 1.023, temp 78, calcium 440
Coral: 3 colors of mushrooms, star polyps, daisy polyps, frog spawn, montipora, xenia, zooanthus, green candy cane, green plate,
octopus coral AND SICK: Fiji Leather, cabbage, plus yellow devil finger leather.
Fish: algae blenny, blue tang, mandarin, clowns, chromis, foxface
Other: emerald/hermit crabs, shrimp, clam, flame scallop, and snails

[jenglish]

I would run carbon in case they are releasing toxins into the water. Well, I guess I should say change your carbon fairly often in case it is getting full. Iodine dips are a good solution to a parasite or infection. They don't seem to be working? makes me think there may be some other cause.

Sorry, I have never kept those softies before I can't shed much light on the subject

[Loverotties]

Originally Posted by jenglish

I can't shed much light on the subject

That's a bad pun!,I agree with what he said,but with high Nitrate you probably have high Phosphate .I do some WC too.

[biowheel]

Welcome to TRT !!
Water changes as stated above . What is your typical maintenance schedule. Sounds like the water column is getting overloaded .

Are you doing 18 gallon water changes ?
If so what are your mixing practices?
Did you change salts ?
Did you change RO/DI water ,places ,LFS
Get a new thermometer and check the water temp
Do you use a refractometer to test salinity ? Hydrometers are not reliable
Just trying to think of everything that might help
Sorry for the trouble
Keep us posted

[James Robert]

Sorry to here about your leathers. I have two leathers, a devils hand and a fiji yellow in a 60 gal. Devils hand for the last year has done great. But the fiji yellow has not polyped in 10 months. I been studying this problem for awhile. IT also turned color with algae. I thank my crabs for cleaning it up. It opens and closes fine . I sounds like you have done your research. Im in the process of experimenting. Just curious, how is your alkalinity. With leathers needs to be on the high side, about 10 to 12. Keep posting .

[Spotster123]

Thanks to everyone for the good suggestions and the warm welcome.

We try and change the water (around 18 gallons) every week to 10 days at most. The water comes from the fish store so we don't mix ourselves and we use fresh from there too for top offs. We use a hydrometer to test so might try a refractometer and new thermometer just to be sure.

Hmmm... we haven't tested for alkalinity or phospates so we'll check that out. (loverotties - great pun BTW)

Thanks again- will let you know if anything works!

Spotster123