oily-look on the surface of the tank

le9569

Around a week ago, I got a hard coral to the tank, couple days later, on the surface of the water, there is something like oily covered on the water. The fishes are stressful. they jump very fast whenever they see people. I wonder what happened. I tested the water and it seems to be fine.

My first guess is there is no Oxygen so the fishs get stressed?

How to treat this problem and how to prevent this oily-like dust on the water surface? You input is truly appreciated.
Thanks

le9569

usmc121581

Lets start with your water parameters. What are they like? And do you have descent water movement along the surface of your tank?

le9569

Yesterday, I tested the water and all levels are acceptable. I do have one header pump blows horizontally to the tank. The other one is for hang-on protein skimmer. There is no pump blows upward.

Do I need to make another water change?

thanks
le9569

Lupin

So does it mean no water movements? Marine tanks will often need water movements.
It doesn't hurt to do another water change.

crazie.eddie

How big is your tank?

What type of filtration are you using?

What model skimmer are you using?

Are you using RO or tap water for water changes?

Are you dosing additives?

le9569

1. My tank is 46GL one
2. I am using Fluval 204 and 304 for Filtration
3. I am using RO water for the tank
4. I using hang-on Prorama protein skimmer
5. I am not sure what you mean by "dosing addictives". what is it, BTW?

I know the tank is quite small and there is not a reef tank (no overflow hole type). For now, it is getting a bit better after I installed the Prorama filter box. Another problem is the floating food is also filter out by it.

Your input is appreciated.
Thanks
le9569

usmc121581

I just removed my hang on the back filter and got the same film on the top. I'm looking into what it could be .My tank is well established so it isn't anything with chemicals or Amm., nitrates, or nitrites. It has to be something else. I will get back with you when I find out. :D

le9569

I talked to one expert and he told me that because there is not enough oxygen down in the tank, some aelgy is dead and floating up. Once it is floating, it creates a oily-like cover on the top of the water and it itself prevents the oxygen from going down. That makes sense, somehow.

I use Promara filterbox for 2 days and it seems to be gone . We need to know the cause to prevent it.

Thanks and we are looking forward to getting your answer :)

le9569