Purple spot in glass

[agordy216]

I have this purple spot in my glass there are a few of them. Can anyone tell me what it is? I was cleaning my glass and seen them they don’t just scrape off with my cleaning tool.
Thank you in advance

Amber

 

[blaxsun]

Could be coralline algae, but most definitely algae. You may need a scraper with a stainless steel blade to get it off.

 

[agordy216]

That is what I tried to use and it didn’t come off… if it is coralline I am fine with it being there.

 

[Asm481]

If it is Coralline you want o scrape it off or else you won't see inside! As you scrape it, it will set up in different more acceptable spots.

 

[blaxsun]

That is what I tried to use and it didn’t come off… if it is coralline I am fine with it being there.

If it's really built-up, some effort may be required. Seachem makes these nice white-handled scrapers that are quite effective.