FISH DYING AND BREATHING HEAVY
 

So on another thread i was reading about some one who had added new powerheads and his fish started dying, same thing has happened to me when I added 2 new powerheads, all parameters are fine so I thought it was just a bit of sediment that the powerheads had stirred up because there was a bit of a film on the top of the water. But in the thread some one said that there is a harmful coating on some powerheads and I should run them in vinegar and water, I'll do that but in the mean time can I set up my new skimmer without there being a coating problem??!! HELP PLEASE!!
I have done about a 40% water change since all this started.

Whats your temperature, power heads increase the temperature.

Temp is 78 and was the whole time the powerheads were in there, I took the powerheads out yesterday.

what type of powerhead is it? could there be some electrical leak into the water?

If they are made for aquarium, they should not have any dangerous coating, at least I hope! I use koralia and never even washed them prior to putting them in the aquarium.

These are brand new koralia 750gph

If the new powerheads are stirring up the sand, it could be releasing toxins that were trapped under the sand.

Well i have a sandsifting goby and it wasnt really stirring up a lot of sand to begin with.

If you have a film on top of the water, that indicates to me that the top of the water is still. ( I don't know if I'm right, just trying to rule stuff out to help you )

Try placing one of the powerheads just a few inches below the water suface (not high enough that it sucks air into the powerhead). Aim the powerhead up so it agitates the surface, this will create "waves" which will help with gas exchange as well as add more oxygen to the water, it will also drop the temperature of the water.

Higher temperature water will decrease the saturated oxygen level in the water. Adding powerheads generally raises the temperature.

Also if your salt level is on the higher end, this also decreases the maximum saturated oxygen level in the water.

Before I took the powerheads out they were like that. And thats when this all happened, salinity is 0.024. Im scared to put the powerheads back in unless i know theyre clean :sad:

The powerheads would have to be dipped in something pretty nasty to cause that much chaos. Diluted to a full tank system, it would have to be something VERY strong to cause something like this. Try looking at other causes, what are your nitrates at? nitrates will strip oxygen from the water faster than anything if they get out of control. You said your skimmer is not hooked up? what are you using for filtration currently? it that leeching nitrates back to the tank?