Odd Duck

Hi! My Betta tank water is VERY green. What I thought was a bacteria bloom was actually what appears to be a phytoplankton bloom 😬😬😬😬 I have tried algaecides, I have tried polishing pads, I have tried a phosphate remover. It only improves after a small water change but comes back within 3 days. Do you have any ideas for what could possibly help? Because I have read every forum and watched every YouTube video for weeks and I can't get it to stop. Thank you in advance.