What is this developing on the side of my tank glass

[PartyHacks]

Have you tested your water?

No

If I did not test my water...

1. ...I recognize that I will likely be asked to do a test, and that water tests are critical for solving freshwater health problems.

Do you do water changes?

Yes

If I do not change my water...

1. ...I recognize that I will likely be recommended to do a water change, and water changes are critical for preventing future freshwater health problems.

My magnet glass cleaner will not clean it.

 

[Rocksor]

green spot algae. scrape it off with regular magic eraser. It's caused by too much light and nutrients from waste/food particles.

 

[duanes]

green spot algae. scrape it off with regular magic eraser. It's caused by too much light and nutrients from waste/food particles.

Agree
It is a normal part of almost all aquarists weekly maintenance.
I use a razor blade for the tough stuff, but if I keep up and not allow it to get a foothold, one of the typical algae magnets work pretty good.

https://hosting.photobucket.com/albums/i97/dstuer/equipment/.highres/027.jpg?width=450&height=278&crop=fill

Above one I made using PVC and a razor blade.