Since the tanks are already built (otherwise constructing with a UV-resistant material would have been an effective option), creating a water cycling system to prevent stagnation, keeping water temperature low (if this is feasible with the intended application), and installing tank liners that can prevent algae adherence to tank walls are some of the measures to take.

To reduce blue algae (cyanobacteria) in a water tank reservoir, you can start by limiting the nutrients that promote their growth, particularly nitrogen and phosphorus, by using chemical treatments such as algaecides or natural alternatives like barley straw. Ensuring proper filtration and regular cleaning of the tank helps remove algae and prevent future blooms. Additionally, reducing sunlight exposure by covering the tank or using shading materials can inhibit algae growth, as blue algae thrive in bright, warm environments.

To reduce blue-green algae (cyanobacteria) in water storage tanks and wastewater treatment systems, it’s essential to control the factors that promote their growth. These include sunlight, nutrients (especially nitrogen and phosphorus), and temperature. Below are tailored strategies for different scenarios:

In Water Tanks (300L, 500L, 1000L, etc.)

1. Shade the Tank

• Prevent Sunlight Exposure: Use opaque tanks or cover transparent tanks with UV-resistant materials to block light.

• Place tanks in shaded areas or paint them with dark, non-toxic coatings.

2. Nutrient Control

• Regularly clean tanks to remove organic matter and sediment.

• Use pre-filtered water to limit nutrient introduction.

3. Aeration and Circulation

• Install aerators or small recirculating pumps to prevent water stagnation and improve oxygen levels.

4. Chemical Treatments

• Add safe, approved algaecides, such as copper sulfate or hydrogen peroxide (ensure compatibility with tank use).

• Use chlorine (within safe limits) to inhibit algae growth.

5. Biological Control

• Introduce beneficial bacteria that compete with algae for nutrients (consult local regulations and suppliers).

Thanks to all for your contributions, it's brings me more ideas to come up with a great solution.