Removing phosphates in a tub with Lanthanum Chloride

[zalick]

I have around 70lbs of rock from old builds over the years. It's been in a box in my attic for probably 10-15yrs. I'm sure it's heavily bound with phosphates.

I've had it in brutes with RO water and been measuring with a hana ULR every couple days. The measurements are all over the place and I know hanna says to not use with RO water. Generally it's between .08 and .1 ppm.

Rather than continuously emptying and wasting all that water I decided to use lanthanum chloride.

My question is this:
If the Lanthanum Chloride binds to the phosphates and forms a precipitate, can I just say pour a whole bottle of LaCl in the bin and it will all bind with all the available phosphates over time?

So could I just pour a gallon in the bin and let it sit for a few weeks so either all the LaCl or all the phosphates would be the limiting factor?

 

[JumboShrimp]

For whatever help it might provide, here are the relevant directions on the bottle of "Agent Green" I have. It says "Lanthanum Chloride Phosphate Remover": "Do not remove more than 1 ppm of phosphate per day. Add 1 ml per 38 L (10 gal) for 1 ppm removal. Do not overdose." Note, however, these dosing instructions regard dosing directly into a living reef tank. Again, I don't know if this is of any use to you with your question about a bin of old rocks. But I tried. LOL. Best wishes!

 

[zalick]

For whatever help it might provide, here are the relevant directions on the bottle of "Agent Green" I have. It says "Lanthanum Chloride Phosphate Remover": "Do not remove more than 1 ppm of phosphate per day. Add 1 ml per 38 L (10 gal) for 1 ppm removal. Do not overdose." Note, however, these dosing instructions regard dosing directly into a living reef tank. Again, I don't know if this is of any use to you with your question about a bin of old rocks. But I tried. LOL. Best wishes!

Thanks! I was just watching Melev's video of dosing directly in to tank. I always thought that was a big no no but he's been doing it for decades!

I'm currently battling low phosphates in my DT, so I'm actually dosing phosphates. But this old rock has so much bound....

 

[Daddy-o]

I have around 70lbs of rock from old builds over the years. It's been in a box in my attic for probably 10-15yrs. I'm sure it's heavily bound with phosphates.

I've had it in brutes with RO water and been measuring with a hana ULR every couple days. The measurements are all over the place and I know hanna says to not use with RO water. Generally it's between .08 and .1 ppm.

Rather than continuously emptying and wasting all that water I decided to use lanthanum chloride.

My question is this:
If the Lanthanum Chloride binds to the phosphates and forms a precipitate, can I just say pour a whole bottle of LaCl in the bin and it will all bind with all the available phosphates over time?

So could I just pour a gallon in the bin and let it sit for a few weeks so either all the LaCl or all the phosphates would be the limiting factor?

I like the aggressive approach when there is no livestock involved. That said, I dont know that I would pour a gallon of LC in. I am not an expert by any means. I do know that after the Lanthanum Chloride has no phosphate to bind with, it will attack alk. (I dont know if this is a concern with just rocks?) Also as the Lanthanam Chloride binds with phosphate and becomes Lanthanum Phosphate, your test kit will read this as phosphate. So even with no free phosphate in your barrel, the test will measure the precipitate and could read high.
Cheers! Mark

 

[zalick]

I like the aggressive approach when there is no livestock involved. That said, I dont know that I would pour a gallon of LC in. I am not an expert by any means. I do know that after the Lanthanum Chloride has no phosphate to bind with, it will attack alk. (I dont know if this is a concern with just rocks?) Also as the Lanthanam Chloride binds with phosphate and becomes Lanthanum Phosphate, your test kit will read this as phosphate. So even with no free phosphate in your barrel, the test will measure the precipitate and could read high.
Cheers! Mark

Thanks. This was the kind of thing I'm looking for. If it attacks alk next it might cause the rock to become more brittle?

I have noticed that when I pour a capful in the bin the water clouds up immediately and then clears after an hour or so. Maybe just keep pouring capfuls in every couple hours until they no longer cause clouding?

I'd love to figure out the easiest and laziest way to remove bound phosphates.

 

[Daddy-o]

On a side note, I run the waste from my R/O into a brute. I soak a lot of my rocks and frag discs. in the barrel. I raised the brute up and have a bulkhead and hose hooked up to the bottom. When it is full, I drain it into the yard. In theory, it is a free soak/rinse.

 

[Daddy-o]

Thanks. This was the kind of thing I'm looking for. If it attacks alk next it might cause the rock to become more brittle?

I have noticed that when I pour a capful in the bin the water clouds up immediately and then clears after an hour or so. Maybe just keep pouring capfuls in every couple hours until they no longer cause clouding?

I'd love to figure out the easiest and laziest way to remove bound phosphates.

Which product are you using?

 

[zalick]

Which product are you using?

I'm using seaclear which I believe i read from Randy is just pure LaCl.

That's a great idea for the waste water. My RO/DI is a 2:1 unit but when I'm making a couple hundred gallons a month it really ads up!

 

[Breadman03]

As I understand, PO4 binds to the rock and it will take time for phosphates to leach out of the rock and back into the water. I suspect that you could start with a daily dose at first before reducing the dosing frequency to once a week or so as phosphates approach desired levels.

 

[zalick]

As I understand, PO4 binds to the rock and it will take time for phosphates to leach out of the rock and back into the water. I suspect that you could start with a daily dose at first before reducing the dosing frequency to once a week or so as phosphates approach desired levels.

As an experiment, and based on Melev's video of dosing LaCl straight in his tank, I've been dumping a couple cap-fulls of LaCl in the tubs every couple days. Initially the water would cloud up right away and after a day it would be clear again. Then it started getting less cloudy. The last couple doses there was no cloudiness.

I haven't tested P yet but it appears the available P in the rocks has all leached out. I'm going to test P today and see.

 

[Daddy-o]

Nice! be sure to rinse all the flocculate out or you will get a false reading (or let the water settle real good)
Cheers! Mark

 

[Randy Holmes-Farley]

So could I just pour a gallon in the bin and let it sit for a few weeks so either all the LaCl or all the phosphates would be the limiting factor?

Lanthanum carbonate will also precipitate, "ruining" much of the lanthanum.

 

[zalick]

Lanthanum carbonate will also precipitate, "ruining" much of the lanthanum.

I thought there might be another reaction when the available P was gone...

Once the Lanthanum Chloride binds to P and precipitates out, will it stay bound as a preferable bond or will the P slowly seek equilibrium in the water again?

Put another way, will slowly dosing Lanthanum Chloride over time, without changing the water, be an effective way to bind the P leaching from the rocks so one can avoid water changes in the tub?

 

[Randy Holmes-Farley]

I thought there might be another reaction when the available P was gone...

Once the Lanthanum Chloride binds to P and precipitates out, will it stay bound as a preferable bond or will the P slowly seek equilibrium in the water again?

Put another way, will slowly dosing Lanthanum Chloride over time, without changing the water, be an effective way to bind the P leaching from the rocks so one can avoid water changes in the tub?

It will stay precipitated until one of two things happens:

1. The lanthanum concentration drops very low for reasons other than lanthanum phosphate precipitation.
2. The phosphate concentration drops very low for reasons other than adding lanthanum.

 

[Daddy-o]

It will stay precipitated until one of two things happens:

1. The lanthanum concentration drops very low for reasons other than lanthanum phosphate precipitation.
2. The phosphate concentration drops very low for reasons other than adding lanthanum.

So the Lanthanum Phosphate can "unbind" and become Lanthanum Chloride again??

 

[tehmadreefer]

For whatever help it might provide, here are the relevant directions on the bottle of "Agent Green" I have. It says "Lanthanum Chloride Phosphate Remover": "Do not remove more than 1 ppm of phosphate per day. Add 1 ml per 38 L (10 gal) for 1 ppm removal. Do not overdose." Note, however, these dosing instructions regard dosing directly into a living reef tank. Again, I don't know if this is of any use to you with your question about a bin of old rocks. But I tried. LOL. Best wishes!

Well obviously you wouldn’t do that in the tank...

 

[tehmadreefer]

Use LC such as seaklear brand. Use a capful as it is very strong and will strip all po4 out, drain, rinse, voila po4 is gone...

 

[Randy Holmes-Farley]

So the Lanthanum Phosphate can "unbind" and become Lanthanum Chloride again??

Lanthanum chloride becomes dissolved lanthanum ions (La+++) and chloride ions ( Cl-) when dissolved in water, The lanthanum and chloride are no longer connected in water.

Lanthanum phosphate will dissolve into lanthanum and phosphate ions if the concentration of either or both is too low, like any ionic solid.

 

[Randy Holmes-Farley]

Following up on that last point, many reefers think dosing lanthanum is somehow "unnatural", but precipitation of lanthanum phosphate is what controls the concentration of ions such as lanthanum in the deep ocean. It precipitates until just enough remains to be in equilibrium. If phosphate was higher, the lanthanum concentration at equilibrium would be lower, and if phosphate was lower, then there would be more lanthanum in solution:

Rare earth precipitation and coprecipitation behavior: The limiting role of PO43− on dissolved rare earth concentrations in seawater

Formation of rare earth phosphate coprecipitates, (ΣMi)PO4(s), may set limits on the maximum REE concentrations observed in seawater. Examination of r…

www.sciencedirect.com

 

[gdabz69]

Thanks! I was just watching Melev's video of dosing directly in to tank. I always thought that was a big no no but he's been doing it for decades!

I'm currently battling low phosphates in my DT, so I'm actually dosing phosphates. But this old rock has so much bound....