Zoas dying off
 

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!

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.

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.

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

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.

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.

Pics

one more

and another

Notice the gorilla nipples in the back are hunky Dori.

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?

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

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.