Some sort of layer

[hyewiz]

I am newbie in all this, and trying to set up 2.5g pico with AC300 as Refug. the tank is under cycle with LR and LS only. Just noticed in the AC300 he water surface looks like a very thin layer of oily, and noticed in the AC300 the water is like stand still although it is flowing in the tank.
any idea? what that could be.
thanks

 

[lando]

Most likely just resadue from the LS. Get a brine shrimp net and skim the surface f the water. Then add a small powerhead and aim it so it ripples the surface of the water. This should help.