How can we avoid water turning green and avoid sunlight as much as possible?

Where the bathtub is placed, it will inevitably be exposed to the sun. The following methods are effective: 1, along the angle of sunlight, shading with shading net (similar to black gauze) can reduce the speed of water quality turning green; 2. If you are raising tropical fish, it is recommended to buy some scavenger fish, which will chew up the green algae in the fish tank (but raising tropical fish is not suitable for direct sunlight); 3, buy a fish tank pump, use activated carbon, the water quality will be good.