i don't have the full picture of your problem, maybe pictures will help greatly .....
However, i will just share some of my experience. Green spots that you mentioned, i doubt they are brown algae that turn green algae. Waterchange 3-4 time a week will help alot. At least 2 times a week. Normally i will just change 80% of water. In one month u may see the difference. Otto and shrimp will be great help for brown algae
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