I have a scrubby on a stick and a 3-in-1 tool that has a scrubby end, a metal blade end, and a gravel rake end. Blades a great for glass, the scrubbies are good for glass or acrylic. Don't use blades on acrylic, they will scratch it up. Scrub the walls before a water change so you can suck up anything you scrape into the tank. You can also use a regular kitchen sponge that has never been used for anything else. Be careful with algae removing chemicals, they are usually not safe for invertebrates and may irritate your fish. Reducing your lighting is the first line of defense for avoiding algae.