General Discussion

coprolite

(368 posts)

16. The DC water system

Tue Jun 23, 2026, 08:01 PM

Yesterday

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, Iâ€™m gonna share my theory as to whatâ€™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) ðŸ´â€â˜ ï¸#OFMDForLifeðŸ´â€â˜ ï¸ ðŸ³ï¸â€ðŸŒˆðŸ¤¡ (@sevensugars.bsky.social) 2026-06-17T17:13:45.979Z

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waterwatcher123 DBoon

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Well I feel rather vindicated... I said the algae problem is likely related to nutrient excess in the water [View all] 31j20b3 Yesterday OP

Oh you! Smarty pants! Giving expertise to this ALBliberal Yesterday #1

Don't throw your science in Trump's face... lame54 Yesterday #2

.."cast not your pearls before swine".. thomski64 Yesterday #14

As my son says UpInArms Yesterday #3

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

Hahaha SuzyandPuffpuff Yesterday #5

Donny's no-stop verbal diarrhea helps the algae bloom struggle4progress Yesterday #6

If the water was pumped directly from the Potomac, no wonder it has an algae problem. waterwatcher123 Yesterday #7

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

So, are you saying the water is treated to Safe Drinking Water Act standards? waterwatcher123 Yesterday #18

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

The water is sourced from the tidal basin... reACTIONary Yesterday #22

From the NYT chia Yesterday #31

Thanks! So it's both, depending. reACTIONary Yesterday #33

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

The DC water system coprolite Yesterday #16

Interesting - solving one problem creates another one. waterwatcher123 Yesterday #19

Your pool has never had algae???? LeftInTX Yesterday #32

Agree. I've said that for a week orthoclad Yesterday #10

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

Algae will find a way! BidenRocks Yesterday #11

... Wednesdays Yesterday #27

Learn something new every day! calimary Yesterday #12

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

Make Algae Grow Again!! thomski64 Yesterday #15

Hey. 1000 posts! progressoid Yesterday #20

I've read that it is sourced... reACTIONary Yesterday #24

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

It looks like it can be either, depending.... reACTIONary Yesterday #34

That would be a huge amount of treated water orthoclad Yesterday #36

You know the Potomac is saturated with nitrates from fertilizer run off. Golf courses are the worst nitrate polluters. flashman13 Yesterday #17

The water has electrolytes. It's what plants crave. Hassin Bin Sober Yesterday #21

Trump knows more about pools than you do. mercuryblues Yesterday #23

Is it possible the cause of the algae is from LogDog75 Yesterday #25

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

I keep thinking about those Pranksters who are planning vanlassie Yesterday #29

Maybe the problem is when the Orange Turd's motocade drove on it LogDog75 22 hrs ago #37