Phosphates.....are they worth removing??

[PoolBrews]

My concern over the use of most phosphate removers is the active ingredient—the substance that actually works on the phosphates—called lanthanum. It’s a soft metal element that’s classified as a rare earth element despite the fact that it’s almost three times more abundant than lead.

Lanthanum is classified as “moderately toxic". While phosphates are indeed a food source for algae, they are not toxic.

In my mind, do I want to add chemicals to my water that are considered toxic? Or just kill it with more chlorine?

 

[JoyfulNoise]

My concern over the use of most phosphate removers is the active ingredient—the substance that actually works on the phosphates—called lanthanum. It’s a soft metal element that’s classified as a rare earth element despite the fact that it’s almost three times more abundant than lead.

Lanthanum is classified as “moderately toxic". While phosphates are indeed a food source for algae, they are not toxic.

In my mind, do I want to add chemicals to my water that are considered toxic? Or just kill it with more chlorine?

It is NOT lanthanum metal but the salt of the metal, lanthanum chloride. The lanthanum ion will immediately react with phosphates and bicarbonate to form insoluble lanthanum phosphate and lanthanum carbonate. Both of those compound completely precipitate out of solution and are trapped in the filter. Once you backwash or clean the filter, the lanthanum is gone from your pool.

The human body does not use lanthanum in any way and it will mostly pass right through your digestive system IF you were to ingest any significant quantity of it. The amount of lanthanum added to the pool water during the process is far below any toxic limit and, as is the case, no one should be swimming in the pool anyway during treatment. Lanthanum chloride has been and can be used in the treatment of drinking water (although it’s not because of the cost and the ready availability of alternative methods) and so if there were any issues with toxicity, the EPA would never allow its use in those contexts.

Please be more careful when posting about chemical toxicity. Any chemical, even salt and chlorine, can be “toxic” or dangerous. Context, dosing and usage matters when discussing issues of toxicity and it’s easy to make things sound much scarier than they are in reality. If a pool owner follows the stated directions on the product label and uses common sense, there is literally no danger of toxicity in using phosphate remover products.

 

[PoolBrews]

Thank you for the clarification! That makes me feel better about using it if my numbers on phosphates get too high. Currently, my phosphates are 150ppb. I think I'm OK for a while.

 

[mguzzy]

I do exactly what @JoyfulNoise does with respect to phosphate removal. One or two treatments in the spring will make things run better throughout the summer I've found. I work it into my springtime soft pool opening routine when I am cleaning the filters anyway.

 

[JoyfulNoise]

Thank you for the clarification! That makes me feel better about using it if my numbers on phosphates get too high. Currently, my phosphates are 150ppm. I think I'm OK for a while.

150ppb (parts per billion) I think is what you meant to write. 150ppm (parts per million) would turn your pool into an all-you-can-eat Vegas casino buffet for algae.

150ppb is very low. I don’t treat unless my phosphates are closer to 1000ppb (1ppm). My municipal water supplier does not use phosphates for water treatment so the only source of PO4 comes from humans and the environment. My phosphate input rate tends to be about 200ppb per season or so.

I’ll be doing a big partial drain and refill of my pool this spring so I’ll have to see where my PO4 levels go. I may or may not have to treat the water.