Brown algae, or diatoms, may eventually go away and you are stuck with the algae eaters and must provide dried algae like waffers. Green spot algae is way too hard for anything to really eat it, it is usually caused by a lack of nutrients I believe, forgot lol... But usually you need a coarse sponge or a razor to get it off, that is when you need to scrape off.
Amano shrimp or nerites snails probably work best, amanos can be fragile though since usually they are wild caught.
15 Gallon NPT
1g no tech bowl in the making