Urgent All help appreciated please

So I decided to add some polyp coral into the tank. A day after the addition of the coral the fish start acting funny. they have been towards the bottom of the tank and not very active. They were eating fine. today, I come to find out since I'm out of state for a few days that the fish aren't eating at all and are getting shivers. Water tests and conditions were good with only nitrates being at 20ppm before I left. And all this started after addition of corals. I have a yellow tang, 2 clowns, 2 domino damsels and 3 blue damsels. I'm really hoping I don't return home to an empty tank. I'm fairly new to the hobby and this is an issue I don't know where to start going with to resolve. I'm thinking a possible toxin from corals??

 

What type of coral?

 

Coral type?

Paramaters?

Water temp?

Why are your nitrates at 20ppm? Should be at 0.

Age of tank?

Size of tank?

Filtration?

 

^ this

 

Coral type....honestly I forgot the names and wrote them down at home. I will update that when I get back in a few days. I just know they are various colony polyps.

water temp constant 79
ammonia, nitrites 0 ph 8.1
SG 1.024

nitrates were at 40 but found the problem using filter socks and after removing those it fell to 20.
refuge with protein skimmer and chaeto and ulva

And also running filter sock with GFO and Carbon.

 

Age of tank???

Size of tank???

 

sorry left that out. age of tank is about 4 1/2 months. and it's a 55 gal

 

The fish are getting shivers makes me think of stray voltage. I had some Oscars that got the shivers about every 3 minutes. I stuck my hand in the tank the same time the heater came on and quickly realized the "shivers" were coming from a cracked heater housing.

Get a digital multi-meter and set the dial to read 200 ACV, unplug all submersed equipment. Put the negative probe on the meter into a ground prong socket, put the positive into the water. It should read 0.0
One at a time plug in your submersed equipment. If the numbers on the meter ever change it means that the particular piece is leaking electricity.

 

Now I could be wrong here, and I'm by no means an expert, and I'm just tossing out an idea... If they're a type of zoas you got, they do carry a potent toxin in them... There could maybe be a release of some of that toxin from the stress of moving...? If so, some carbon in high water flow could suck all that up.

Just tossing out an idea... Maybe someone with more coral knowledge could chime in on that

 

that was a thought that crossed my mind and I can't wait to get back from this job related travel to check my equipment.