Lee,
Do you have any algae eaters in your aquarium yet? I couldn't remember what fish you have. If you don't have any algae eaters I would recommend you get a few to help keep the algae from growing on your plants and aquarium walls.
Maybe a few fish called Otocinclus algae eaters, or another fish called Flying Fox algae eaters would work great.
If the algae on the sides of your tank is really hard and hard to wipe off, ask your dad to use a metal edged algae scraper to scrape it off or show you how to use one.
