Welcome back
I only clean my back glass 'when I feel like it', so I probably have some of what you do. That stuff won't come off very easily with my easy blade attachment
For that really heavy/thick stuff I like to use a Kent Pro Scraper with the
Stainless attachment
The coralline and other stuff comes off with hardly any effort at all, and the blade takes off film stuff too
The new Kent ProScraper II is a kit and comes in a couple different lengths