When cleaning an acrylic aquarium you want to get it really clean, make it safe for the fish and make sure it is eco-friendly.
White vinegar cleans the mineral deposits on a tank. Simply put some on a small towel and wipe the towel on the line of deposits. You can use it to clean rocks and aquarium ornaments. You can also dilute it in water and spray it on the glass to clean it. Be sure to use a soft cotton cloth to wipe it down instead of paper towels since they can scratch acrylic. If there is residue you need to scrape off use a plastic razor blade.
Instead of using extra chemicals when cleaning algae from a tank, use an algae scraper. Get a scraper from a pet supply store as a hardware store scraper might have chemical residue that could harm the fish or it might scratch the acrylic.
If you decide to buy a commercial cleaning product get one that is designed to be aquarium safe. Cleaning products with ammonia or lime can kill the fish. You can find eco-friendly cleaners made especially for cleaning an aquarium in spray form or in wet wipes. Be sure the label recommends it for acrylic tanks. Some of these are formulated to resist fingerprints and repel dust.