Marine Problem - Urgent Help Needed

[Arimus]

12 US Gallon nano tank

Water Parameters:
Ammonia 0.5ppm
Nitrite 0.5ppm
Nitrate 10ppm
Ph 8.4
Temp: 24 C / 75.2 F
Salinity 1.020 (on the low side - now raising)

Corals:
1x Pulse Coral
1x Leather
1x Orange Sponge
1x Lime green coral
1x Hammerhead (small - very small)
1x Yellow something or other (will dig the correct name out when I have more time)

Fish:
1x Yellow-tail damsel
1x Scooter blenny (actually a dragonette)
1x Black clown
1x Rainbow Blenny

All the fish seem very subdued - almost dead - but are still alive - the cleaner shrimp seem ok - hermit crabs are possibly ok but hiding as usual...

The tank is a nano tank with filter built in - filter is currently:
chamber 1: coarse sponge, live sand, activated carbon
chamber 2: phosphor remover, bio balls, ceramic rings.
chamber 3: the pump and heater.

Only change today has been addition of the hammerhead and use of D&D aquascape construction putty to stick some of the corals down in their proper places.

Anyone got any ideas as to why in the last two hours all the fish have gone from healthy to close to death?

 

[WILDER]

You need to post this in the marine section of the fourm.
Looking at your stats the tanks saying uncycled.
I would do an immediate water change.
Them post this thread in the marine section of the forum.

 

[Arimus]

The nitrite has just come back up today - was down to 0 (ditto ammonia).

Going to do a water change now.

Having said that everyone looked fine since being added (the clown and damsel have been resident for a week, the scooter since Friday last week and the rainbow this weekend)...

 

[WILDER]

Post here.
http/www.fishforums.net/category/19/Mari...Reef-Chit-Chat/