Zoas dying off

[paulbop]

I have had Zoa colonies that have exploded over the last 2 years that are dying on one end of the colony and spreading on the other. This is happening in multiple places in my tank.

I added IPSF.com refugium startup kit to my refugium to add some diversity to the tank. I am not sure if this started before or after. It included 5 Types of Macro Algae. Marine plankton, worm pack, and anthropods.

I cannot see any visible parasites (maybe I am not looking correctly). Some colored zoos are being affected while others are untouched. Very confused but I am losing Zoas that I have had for years and do not know why. Please help.
90 gallon tank with 20 gallon mud/sand refugium sump.

Ammonia 0
Nitrites 0
Nitrates 20ppm
Ca 420 ppm
Ph 8.1

Running a marineland skimmer (productive) and a filter sock. 1200 gph return pump and 900 gph koralia. Natural Macro algae/live rock filtration. I am currently dosing Purple up 2 capfuls every few days. I started the purple up after this started (hoping it was a trace element problem). Didnt work but my tank is growing more purple every day!

Thanks for you help guys and gals!

[brad65ford]

2 years and everything was going well then things went down hill, I feel ya bro. Did you add a new coral recently? Would love to see some pics.

[paulbop]

no new corals. Just the refugium stuff. Maybe I need to change my bulbs on my lights. Its been 6 months on my MH bulb and a little less on my cf's.

[MikeandNicole]

Interesting, do you have pictures of the area that is dying off?

[paulbop]

I can photo them when I get home but they are closed up mostly and the ones that are open look sickly and deflated. The areas that have been closed for a week or two are just dissolving away. These were healthy growing colonies just a month ago. The thing that is puzzling is that only certain colored zoas seem to be affected.

[MikeandNicole]

Can you remove the colonies at all? If so you might want to try a revive and furan II baths just to see.

Pictures help, something might not be out of place for you but could be quite obvious to someone on here.

[paulbop]

Pics

[paulbop]

one more

[paulbop]

and another

[paulbop]

Notice the gorilla nipples in the back are hunky Dori.

[gh0st]

A couple of those pics, I would blame the nearby hairy mushrooms, they can pack a sting as well as releasing aleopathic toxins.

Give them some space, and possibly increase flow a bit.

Nitrates can cause some polyp shrinkage as well, your levels aren't bad at 20, but probably not helping either. Try and bump the PH up a smidge as well to 8.2-8.4.

What is the Alkalinity like?

[paulbop]

I test for KH and it was around 180. I just did another test and I seem to be having a nitrate spike. It was around 60. I think that could possibly explain it. As far as the mushies they have been next to them for 6 months with no problem and it is happening in other parts of the tank with no mushrooms. I need to get my nitrates down. Any suggestions on that. I have noticed the red seaweed that I got from IPSF is dying off. Maybe that is causing the spike

[Attreui]

Also possible the Zoos dying off is increasing the nitrates. The fastest solution for the Nitrates is a water change. It will lower them quickly and you will need to keep an eye on them during the die off.