What's growing on my glass wall?

[Hipertec]

I'm getting these brown film growing on my 28g nano tank glass wall:

I would use my cleaner magnet and it would come back in a day.

Any idea what the film is and how to slow it down/get rid of it? The tanks been running for about 5 months and the corals/fishes are doing well.

 

[Supurderek]

Probably a mini cycle/diatom outbreak. Usually if it comes back that fast, cutting back light may slow it down. What are your parameters and type of lighting/cycle?

 

[Liti]

I used to get the same also, I second diatom or another type of algae. I installed a UV filter and that seemed to slow it down significantly. I also added JBL silicatEX to my reactor and that helped a lot.

 

[ahiggins]

I get it too, it comes off with a magnet cleaner. I usually clean it off once a week

 

[Hipertec]

My lighting is the stock jbj advanced nano hood. Led at 89watts- I changed a few leds to royal blue 15pcs and 10pc of 14k whites. I'll be adding 4 UV 410nm when it comes in to replace some of the whites.
Will check the parameters tonight.
Just a pain always growing back the next day.

 

[LetItReef]

I get that too and I think because my tank is near a window with shutter which is closed.
It does comes off easily with a magnet cleaner but I have to clean it everyday.