Well I feel rather vindicated... I said the algae problem is likely related to nutrient excess in the water

[chia]

30. No, I'm not saying that. According to the NYT:

Water is pumped from the Tidal Basin, an inlet of the Potomac River, to the treatment plant. There it is filtered and purified before being fed into the Reflecting Pool. But when the water from the Tidal Basin is too murky or filled with algae — which is often — the pool is filled with city drinking water instead. This happens especially in the hot summer months, when algae blooms are prevalent.

No matter where the water comes from — the Tidal Basin or the city — it does not stay clean for long. In warm weather, the shallow pool bakes in the sun.

The treatment plant is supposed to combat this problem, using screens and sand to filter the water and a system that infuses the water with ozone gas, which kills algae and bacteria. The first Trump administration had called for an upgraded ozone system to make the treatment more effective. This year, the Trump administration is spending $1.7 million to buy one.

Then there is the matter of the pipes. Water is fed into the Reflecting Pool from the treatment plant and continuously cycled back to be treated and reused.

https://www.nytimes.com/interactive/2026/05/31/us/trump-reflecting-pool-problems.html