Hi everyone,
I have a 12 year old RES in a 100 gallon aquarium. Recently I did a water change, and a week later this white film appeared on the water. I have never had this happen before. I do monthly water changes (partial), as the water always stays pretty clear with the filter. I will make another water change again and will clean up the filter (RENA XP4). Hopefully that will clear it up. I have uploaded a picture here: https://imgur.com/a/vldc9
Do you guys have any idea what it could be and should I be worried about it?
Thanks!