Oily sheen on water surface.

[Poseidons Reef]

I have the redsea nano 53 gal AIO.
It’s been running for three months. I have a few fish and couple of tester corals. Recently I’ve noticed an oily like sheen on the surface of the water. What may be causing this, can it cause harm to the occupants and what would you do to correct this.
Thank you - Poseidons Reef.

 

[Justfebreezeit]

The surface skimming is inadequate. In aios this is normally because the flow isn't enough or angled in a way that it blocks it from going down the overflow

 

[c4haskett]

The film is caused by dust and the oils from the food you feed the tank. It won't harm anything though. You need to add some more flow to the surface to push it into the overflow. They also sell cheap little surface skimmers on amazon you could put in every few days when it builds back up. Curious as to why your overflow now isn't pulling it out. Do you have a picture of your weir/overflow?

 

[Mr. Mojo Rising]

Add more surface agitation, for that size tank you might need some powerheads in addition to the return flow. Place the powerheads close to the surface and aim them upwards to mix that into the water so your filtration can filter it out.

 

[Poseidons Reef]

The film is caused by dust and the oils from the food you feed the tank. It won't harm anything though. You need to add some more flow to the surface to push it into the overflow. They also sell cheap little surface skimmers on amazon you could put in every few days when it builds back up. Curious as to why your overflow now isn't pulling it out. Do you have a picture of your weir/overflow?

 

[c4haskett]

The film is caused by dust and the oils from the food you feed the tank. It won't harm anything though. You need to add some more flow to the surface to push it into the overflow. They also sell cheap little surface skimmers on amazon you could put in every few days when it builds back up. Curious as to why your overflow now isn't pulling it out. Do you have a picture of your weir/overflow?

Nothing really pops out as being off. Like others have mentioned, more surface flow towards the overflow.

 

[dvgyfresh]

Could be too much water in tank not allowing AIO to filter effectively or not enough surface agitation

 

[dvgyfresh]

The chambers in the back, should be cascading and creating small waterfalls