This is the back wall of my 120g (lights are off right now).I’m fairly new, only started a year and a half ago, and this tank has been up for just over a year. Whenever I preform a water change, my girlfriend says she doesn’t want me to scrape the back glass because she likes the look of the algae. I just wanted to see if keeping the algae on the back of the glass and not scraping it could have any negative effects on my tank. I have GSP, zoas, and some xenia right now and I don’t want it to possibly effect their growth, or the health of my fish. Just wanted to see if there’s any experts out there that would be able to help. Thanks!