Green Algae Question

I've had several different types of algae on my side and back of the tank which my Blenny usually eats up once it starts to spread however there's some green algae he won't touch and it has been building up to a point where I think its going to get annoying to scrap off since I have an acrylic tank and don't want to scratch it.

My question is, does anyone know of any good inverts which do a good job cleaning green algae on glass or any good ideas for removing tough algae off of acrylic glass? I've been using a sponge with a rough back and it works but takes some serious scrubbing, else my fingernails will take it off too but that stinks.

Thanks!

 

Use a credit card to remove. Astreae and Trochus snails might remove it when it gets large. Try and get a pic so we can try and help you identify the algae.

 

Get an acrylic safe scraper. They work well.

 

Hm, I'll try a credit card. I'll post a pic of it shortly. Thanks!

 

Here's a pic for identification: