Lanthanum chloride - how does Lanthanum get into water?

Reefer1978 · Jan 4, 2025

Good morning @Randy Holmes-Farley, hope you can help me understand how does Lanthanum get into water from Lanthanum chloride dosing? Is it length of exposure to water, or just adding it to a water mixture is enough?

An idea I had this morning (but it's likely not to work), is to remove a significant amount of water from the tank, lets say a 65g drum, dose a large amount of Lanthanum chloride, enough to fully bind phosphate while circulating the water in the tank, and then filter out precipitant through a 1 or 5 micron sediment filter on the way back to the tank. Would that work, or would Lanthanum still get into the water?

Randy Holmes-Farley · Jan 4, 2025

It seems generally very undesirable to drop phosphate more than a little each day.

Any time lanthanum is added, it is instantly available as lanthanum ion, ready to precipitate as lanthanum phosphate, lanthanum oxide/carbonate, and maybe other things.

The removal and return would likely reduce free lanthanum in the water since it has more time to precipitate before encountering organisms, and it may also be easier to remove particulates.

But for reasons in the first sentence, I’d only do it on small amounts of water each day, and then it becomes a lot of work.

Reefer1978 · Jan 4, 2025

Randy Holmes-Farley said:
It seems generally very undesirable to drop phosphate more than a little each day.

Any time lanthanum is added, it is instantly available as lanthanum ion, ready to precipitate as lanthanum phosphate, lanthanum oxide/carbonate, and maybe other things.

The removal and return would likely reduce free lanthanum in the water since it has more time to precipitate before encountering organisms, and it may also be easier to remove particulates.

But for reasons in the first sentence, I’d only do it on small amounts of water each day, and then it becomes a lot of work.

Thank you Randy. It's a large tank, 65 gallons would be a quarter of the water. I am only looking to drop Phosphate 20-25% as my readings are pretty high, and dripping into a 5 micron filter sock is not working, I am spending more time washing the socks than anything else.

Randy Holmes-Farley · Jan 4, 2025

Reefer1978 said:
Thank you Randy. It's a large tank, 65 gallons would be a quarter of the water. I am only looking to drop Phosphate 20-25% as my readings are pretty high, and dripping into a 5 micron filter sock is not working, I am spending more time washing the socks than anything else.

What does it mean that it is not working? It can take a lot to strip phosphate from the rock and sand as it lowers.