500l fish tank with filter and equipment

Cant stop my small pond going green in a few days tried many things got plants a box filter plus a small filler any help plz will a uv light do it

Dose anyone know anyone that has a spare filter in Birmingham big help thank you

Building a sleeper pond 2.4x1.2x0.8m and gathering equipment as I go. I am in need of a retro bottom drain, decent liner, pond glass approx 1000x 600 ish, waterfall feature, bog filter box. Looking for secondhand around the Huddersfield / Leeds area please?

Anyone selling any filters looking for a box type filter with uv and pump not looking for gravity one