Lost my tang and a clown? no idea why
 

salinity was at 31 .. nitrite was .1 barley reading.. ph was fine.. no idea why.. they seem to get this little bit of film on them, then the next day there dropping like flies?? not to sure whats going on but everything was doing really well up untill this? any ideas?

What led up to the deaths?
Was the fish scratching or going to the surface for air?
What is the size of your tank?
When did you set it up? When did you add the fish?

hey
 

no there werent doing anything like that they were being completley normal... its a 30 gallon.. the tank has been up and running for a 2 months the clowns have been in it for a month and a half they were fine.. the tang was added 2 weeks ago and seemed fine aswell.. other stuff in the tank is a clean up crew 6 hermits and 4 snails.. a cleaner shrimp.. not to sure what went wrong

Saltinity seems high,don't know if that would have caused their demise though,I keep my saltinity at 1.025.

hey
 

31 is about 1.024 with what im using to measure, just would be nice to know what happened because that was an expensive accident

what about water movement to produce oxygen in water overnight ... with lights off in a tank and not much surface movement with water.. oxygen leaves tank alot quicker ....

hey
 

i was told to leave my light off to let the shrimp clean whatever was on them off? should i turn my tank light on?? and it has a marineland filter it pushes alot of water in there for sure.. and there is alot of surface movment on the water

I Think this was an oxygen issue, like the others have touched on. Tangs love oxygenated water, which sounds like there wasn't alot to begin with, since the aquarium is only 30 gallons and only water movement is from a marineland filter. Tangs need alot of space 30 gallons wouldn't have cut it and most tangs need at least a four foot long tank to swim in.

hey
 

the marineland is for a 50 gallon is pushes quite a bit of water.. should i turn the light on the save my last clown??? the reason i got the tang was because i was going to upgrade to a 125 .. but so far this takes some time to get used to.. the all the fish last night almost looked like they were shedding.. not to sure what went wrong exactly but sure dont like losing fish

1. Your tank likely did not finish cycling because your ammonia and nitrite readings should be zero at all times. As tjere was no scratching or gasping for air, this was the likely cause of the death of all you fish.
2. Once you have measured to ensure you have zero readings you should wait one month before you add fish and than only add one fish each month. Success in this hobby relies on patience.
3. Did you tell your LFS you only have a 30 gallon tank?
Tangs require a 6' tank that provides them with the swimming room they need. Please wait until you have a suitable tank to accommodate a tang.