New scrubber for my system, last hope

[vinchud]

Hi Mr Monica, its been awhile as i took on board what you said and i thought i would allow the screen to mature for some time as to stop asking such frequent questions.
The Flow was turned up to max and gentle credit card rubbing once a week .
The algae growth was green and still is but far less as you can see in the attached pics ive got some real hard stuck on dark stuff that dont want to come off so ive left it on
The hard stuff is spreading slowly.
I am worried this hard stuff is not exporting what i needs to?
before scape and after

Thanks

[SantaMonica]

You need to scrape all of it off. Use a metal scraper if you need to.

[vinchud]

okay will do thanks

[Bacon]

I read that you can use one of those plastic kitchen scrapers like for scraping pans. Those are much stiffer than a credit card.