Film and bubbles on water surface -- New(ish) Supershrimp Bowl

[tonytheshark]

Hello all, I recently started a 1.5 gallon supershrimp bowl (15 shrimp) with no filter or any other equipment (as recommended). After a couple of months to cycle the tank, the shrimp have been in for about 3 weeks now and seem to be doing well.

Some sort of film has developed on the surface of the water that looks kind of gross. There are also some small bubbles that do not go away on their own. I just want to make sure this is normal and okay for the shrimp.

Pics:
https://i.imgur.com/hBUQCQU.jpg
https://i.imgur.com/XImfszp.jpg
https://i.imgur.com/HnoAjOV.jpg
https://i.imgur.com/eos8CMB.jpg
https://i.imgur.com/tQa5IdC.jpg
https://i.imgur.com/p18ZYCm.jpg

I use RO water and SG is about 1.012. I've only fed the shrimp once so far--2 small algae wafers that I removed after 3 hours of letting them snack.

Thanks!

[Varanus]

Since the water is still, its normal for it to develop a film of algae and other biofilm on the surface. If you get snails you will even see them crawl along the surface film, munching away at it and leaving trails in the brown/green. In my tank the shrimp and snails eventually ate away the film to the point that the water surface looks pretty perfectly clear.

As for the bubbles, they may be coming from the macroalgae as it produces oxygen, or from some biological processes in the substrate. Either way it shouldn't be anything to worry about.

[tonytheshark]

Awesome, I had a feeling it would be okay but I wanted to make sure. Thanks for the help!

Is brackish/salt water normally kind of bubbly? When I topped it off with RO water yesterday the surface disturbance from pouring the water caused some bubbles to form and remain for a long time like soap bubbles might.

[Varanus]

I don't really know myself, if I were to speculate perhaps the bubbles in that situation somehow came from the RO water not mixing quickly enough with the brackish water. Or air bubbles got trapped under the water as the water was poured in.

[Mustafa]

Or air bubbles got trapped under the water as the water was poured in.

That's usually it!