Film on water at night

[trae*]

At night when we are in the hot tub I have been noticing what looks like film on the water near the lights when on.What could this be? During the day my water is clear

pool is pretty new if that matters little over a month old


numbers are all in range

fc - 5
ph 7.4
ta - 100
ch -230
cya -35

 

[HiddenRiver]

This is a guess—could it be skin care products from those in the tub? You might see this at night with artificial light but the sunlight may prevent you from seeing it during the day?


40,400 gallons, 24 x 40, gunnite, DE Hayward Filter, 1.5 HP single speed pump---old everything but tile and coping, Chester County, PA