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

[31j20b3]

that was recovered from the Potomac..cuz you can't grow any plant without nurtrients.

Turns out the genus of algae in the relecting pool is Scenedesmus. snd that it is considered a bio-indicator species of eutrophic (nutrient overloaded) water systems

How about that... a PHD in ecological modelling rom 1988 isn't completely redundant at this point

[ALBliberal]

1. Oh you! Smarty pants! Giving expertise to this

Non scientific regime!

Hope that passes as sarcasm you make a brilliant point!

[lame54]

2. Don't throw your science in Trump's face...

He's got everything handled

[thomski64]

14. .."cast not your pearls before swine"..

[UpInArms]

3. As my son says

Science doesn’t care what you believe …

Thank you for your science!

[TheRickles]

4. But the sign specifically says "Do not feed the algae!".

[SuzyandPuffpuff]

5. Hahaha

You deserve a BAM! 😂

[struggle4progress]

6. Donny's no-stop verbal diarrhea helps the algae bloom

[waterwatcher123]

7. If the water was pumped directly from the Potomac, no wonder it has an algae problem.

Most states and tribes have water quality standards that apply to all water bodies based on use. D.C. is not recognized as a state. So, the water quality standards articulated in the Clean Water Act apply to the Potomac River (source) as it flows through DC. Maryland has already completed major work to identify and remedy a host of pollutants in the Potomac River Watershed and Virginia is likely following suit. So, someone should ask Trump and his minions why the federal government is so inept that it cannot do the same in the District of Columbia (https://experience.arcgis.com/experience/40f9bf562aeb443c859059fa066575c3?org=maryland).

Most states and international agreements consider excessive algae growth to be an indicator of impairment. If these fools think they can simply drain the reflecting pool and refill it from the same source, it will be Deja vu all over again. I suspect discharging this water with high concentrations of hydrogen peroxide is also a violation of the Clean Water Act (the Park Service is not exempt from meeting the requirements of the Clean Water Act). Normally, the Park Service would not dare discharge this water without a concurrence from EPA. But this EPA is simply a rubber stamp for this fascist administration that does not care about laws, and why they were enacted in the first place.

[chia]

9. It's not pumped directly from the Potomac. The Potomac water goes through a treatment facility first

[waterwatcher123]

18. So, are you saying the water is treated to Safe Drinking Water Act standards?

Nutrients are incredibly hard to remove from the water column. Other than reverse osmosis or distillation, dissolved nitrogen and phosphorous are there to stay unless they are removed by plants. Lake associations and conservation organizations often rely on flocculents to remove nuisance algae, where it then sinks to the bottom and is stored in sediment ready to be re-suspended back into the water column with the next big storm (not exactly a solution).

[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

[reACTIONary]

22. The water is sourced from the tidal basin...

... and is filtered before going into the reflecting pool. It is not treated drinking water from the municipal supply. Filtration would remove some contaminates, but I don't think it would remove the dissolved nitrogen and phosphorus that promote algae growth. Or the single cell algae.

[chia]

31. From the NYT

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

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.

[reACTIONary]

33. Thanks! So it's both, depending.

[msongs]

8. why not use tap water and chlorine, like my 60 yr old swim pool that's never had algae

[coprolite]

16. The DC water system

Washington DC like most major metropolitan areas, adds orthophosphate to the water for lead corrosion control.

Algae loves this stuff at the concentrations used.

Since I did do my PhD in cyanobacteria growth and treatment optimization modeling AND work in the water treatment industry, I’m gonna share my theory as to what’s happening here and how to fix it.

People are focusing on the painted bottom of the pool increasing residual heat, and while that 1/19

— Buttons (Ashley) 🏴‍☠️#OFMDForLife🏴‍☠️ 🏳️‍🌈🤡 (@sevensugars.bsky.social) 2026-06-17T17:13:45.979Z

[waterwatcher123]

19. Interesting - solving one problem creates another one.

[LeftInTX]

32. Your pool has never had algae????

Man. I had one six years and all I did was fight algae. It was an above-ground pool with a pump and filter. It was too close to trees, but that was the only level spot on my property.

[orthoclad]

10. Agree. I've said that for a week

https://democraticunderground.com/?com=view_post&forum=1002&pid=21310159

They filled it with N and P enriched river water, and strained out all the animals which would graze on the algae. Under these conditions, it's no surprise that eutrophic-adapted species will dominate.

And now the algae population has reached the limit of the nutrients; recent pictures look yellowish, and there are reports of it stinking.
https://www.democraticunderground.com/?com=view_post&forum=1002&pid=21320375

Next, they will drain it and refill it with fresh river water, starting the cycle over again with fresh nutrients.
https://www.democraticunderground.com/100221323011#post3

I think most aquarium fanciers understand more than the "builder" in the White House.

[vanlassie]

28. That water they want to drain is polluted as well with paint.

Yuck.

[BidenRocks]

11. Algae will find a way!

[Wednesdays]

27. ...

[calimary]

12. Learn something new every day!

[highplainsdem]

13. The NY Times says the pool was filled with D.C. municipal water treated with phosphate, which feeds algae.

https://www.nytimes.com/2026/06/23/us/trump-reflecting-pool-green-peeling.htm

Though Mr. Trump claimed vandals dumped fertilizer in the pool, his administration refilled it with D.C. municipal water, which is treated with phosphate to keep lead from leaching out of old pipes. But phosphate also provides nutrients for algae, as do droppings from ducks swimming in the pool.

[thomski64]

15. Make Algae Grow Again!!

[progressoid]

20. Hey. 1000 posts!

[reACTIONary]

24. I've read that it is sourced...

....from the tidal basin, which is basically river water with no treatment. It used to be DC municipal water, but that was changed.

[highplainsdem]

26. I just posted what the NYT reported today. I don't know who has the correct information, or if any info

from the Trump regime can be trusted.

[reACTIONary]

34. It looks like it can be either, depending....

... Tidal basin with municipal as a backup.

[orthoclad]

36. That would be a huge amount of treated water

purified to drinking standards. Using 2028x165x2.5 gives about 6.3 million gallons of water.

The much cheaper solution is using filtered Tidal Basin water. Filtration will remove particulate matter, but not much dissolved nutrient.

Knowing this gang, I would lay odds they used the cheaper solution, but it would be interesting to see documentation.

[flashman13]

17. You know the Potomac is saturated with nitrates from fertilizer run off. Golf courses are the worst nitrate polluters.

Google lists 6 courses immediately nearby in D.C. and Virginia. Trump's is a 2x18 hole course. Another one is 1x18 and 2x9 hole course. There are many more in Maryland.

IMHO the only way to begin to get a handle on the algae is to paint the pool as bright of white as possible to reduce the water temperature. You would also want to turn over 100% of the water at least once a day. I don't know the capabilities of the pool plumbing system. A new system might be required. Any way you look at it, that is a lot of pumping power. Maybe you could send the electric bill to Donny.

There are also ways to neutralize the nitrates, but that is done with chemicals. I'm not a big fan of chemical fixes. However, it is done in some municipal water supply operations.

[Hassin Bin Sober]

21. The water has electrolytes. It's what plants crave.

[mercuryblues]

23. Trump knows more about pools than you do.

And he says you're wrong. So, Na-NA-NA Boo-Boo.

[LogDog75]

25. Is it possible the cause of the algae is from

ducks that use both the Tidal Basin and the Reflecting Pool. It might be possible that the algae attached itself to the ducks' feathers and when the ducks landed in the Reflection Pool the algae transferred to the water causing it to bloom.

Who really knows what the cause is but I seriously doubt someone intently put algae in the pool.

[LeftInTX]

35. I had a pool. Algae was 24/7. No ducks. But pollen was likely source.

Algae was always worse after pollen events. Also rain events were notorious for dropping dirty plant material in the pool. Once again, more algae.

That pool will always have algae unless they turn into the Bellagio fountains.

The lake contains 22 million gallons of water.[55] It is partly filled with well water, which was previously used for the Dunes golf course. The lake uses two-thirds of the water previously used for the course.[56] Water from the resort's aquatic show, O, also drains into the lake.[57]

Approximately 12 million gallons are used each year for the fountain shows,[55] and the lake uses roughly 500 pounds of chlorine per day.[54] Several restaurants at the Bellagio resort are situated to overlook the lake.[58] The water temperature ranges from 50 degrees in the winter to 85 degrees in the summer.[39] It is frequented by ducks,[36][39] some of which have made it their permanent home.[59]

The operating and maintenance team works in a hidden cavern known as the Batcave,[39][36][20] located within a fake rock formation beside the lake. The Batcave contains four equipment rooms.[8][25][34] The team consists of 30 people, including computer technicians, electricians, and welders. Due to the amount of time spent in the water, all team members are trained scuba divers.[54][36][25]https://en.wikipedia.org/wiki/Fountains_of_Bellagio

[vanlassie]

29. I keep thinking about those Pranksters who are planning

To do something celebratory with hundreds of dildos at the 250 Celebration. I hope they stay far far away from the pool.