DIY Lanthanum Dosing

[schooncw]

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[Jake Martensen]

Someone asked for a DIY lanthanum dosing recipe.

Be sure you understand that some folks have issues with fish (especially tangs) before embarking on lanthanum dosing.

it is also preferable to catch as many of the solids that precipitate out as you can, so dosing before some sort of mechanical filtration is desirable. Many folks use a filter sock.

Finally, note that lanthanum dosing will tend to drop alkalinity a bit, both from binding phosphate and from forming some lanthanum carbonate.

OK, so here's the rationale...

Lanthanum precipitates phosphate as LaPO4. Thus, each one lanthanum ion will remove one phosphate ion (ignoring lanthanum that ends up in other compounds, such as lanthanum carbonate, bound to organics, or remains dissolved in the water).

One phosphate weighs 95 grams per mole
One lanthanum weighs 139 g/mole

Thus, one mg of lanthanum ion removes 0.68 mg of phosphate.

I was asked to use lanthanum chloride heptahydrate ( Lacl3 7H2o; mw 371.5 g/mole) ) to make the dosing solution.

That material is 37% lanthanum by weight.

Dissolve 9 grams (~2 level teaspoons) of lanthanum chloride heptahydrate in water to make 500 mL total.

That solution contains 6.7 grams/L (3.33 g/500 mL)of lanthanum, or 6.7 mg/mL.

Let's pick a dosing volume of 1 mL, so we are dosing 6.7 mg of lanthanum, which will remove 6.7 x 0.68 = 4.6 mg of phosphate.

If that is added to an aquarium that has a total volume of 100 L, then we will be expecting to remove about 4.6 mg/100 L = 0.046 mg/L (~0.047 ppm) of phosphate.

Remember that due to binding to rock and sand, and release from that reservoir when you try to lower phosphate, one may see phosphate come back up close to the starting point within a day or two after dosing, and lowering phosphate can be a lengthy process.

Thank you for this info. Please let me know if you see an error in my plan below.
My phosphate is at .9 for a total system volume of 375 gallons

1. Make the Lanthanum Chloride (LC) solution: Dissolve 9 grams (~2 level teaspoons) of lanthanum chloride heptahydrate in RODI water to make 500 mL (16 oz) total of phosphate reducing LC solution.

2. Using the dosing info above... 1.14 per ml per 100 gallons mixed
1.14 ml = X x = 4.275 ml
100 gallons 375 gallons

3. I will mix 4.275 ml of the LC solution into about 2 gallons of RODI

4. Set my drip to go through a micron sock into the sump over a 24 hr period

5. Dose 1 time, monitor the fish and phosphate levels daily over the course of a week and document the changes every day to establish a baseline, then the following week adjust accordingly.

Any feedback is greatly appreciated! Please be completely honest as I have thick skin. lol
Thanks!

 

[Pistondog]

Thank you for this info. Please let me know if you see an error in my plan below.
My phosphate is at .9 for a total system volume of 375 gallons

1. Make the Lanthanum Chloride (LC) solution: Dissolve 9 grams (~2 level teaspoons) of lanthanum chloride heptahydrate in RODI water to make 500 mL (16 oz) total of phosphate reducing LC solution.

2. Using the dosing info above... 1.14 per ml per 100 gallons mixed
1.14 ml = X x = 4.275 ml
100 gallons 375 gallons

3. I will mix 4.275 ml of the LC solution into about 2 gallons of RODI

4. Set my drip to go through a micron sock into the sump over a 24 hr period

5. Dose 1 time, monitor the fish and phosphate levels daily over the course of a week and document the changes every day to establish a baseline, then the following week adjust accordingly.

Any feedback is greatly appreciated! Please be completely honest as I have thick skin. lol
Thanks!

(I did not check your math)
We drip into the overflow which is caught by 5 micron sock. This would increase the lc contact time before the filter sock.

 

[Randy Holmes-Farley]

Thank you for this info. Please let me know if you see an error in my plan below.
My phosphate is at .9 for a total system volume of 375 gallons

1. Make the Lanthanum Chloride (LC) solution: Dissolve 9 grams (~2 level teaspoons) of lanthanum chloride heptahydrate in RODI water to make 500 mL (16 oz) total of phosphate reducing LC solution.

2. Using the dosing info above... 1.14 per ml per 100 gallons mixed
1.14 ml = X x = 4.275 ml
100 gallons 375 gallons

3. I will mix 4.275 ml of the LC solution into about 2 gallons of RODI

4. Set my drip to go through a micron sock into the sump over a 24 hr period

5. Dose 1 time, monitor the fish and phosphate levels daily over the course of a week and document the changes every day to establish a baseline, then the following week adjust accordingly.

Any feedback is greatly appreciated! Please be completely honest as I have thick skin. lol
Thanks!

The math has an issue, making you go more slowly, but that 's OK.

I said:

Let's pick a dosing volume of 1 mL, so we are dosing 6.7 mg of lanthanum, which will remove 6.7 x 0.68 = 4.6 mg of phosphate.

If that is added to an aquarium that has a total volume of 100 L, then we will be expecting to remove about 4.6 mg/100 L = 0.046 mg/L (~0.047 ppm) of phosphate.

But you calculated per 100 gallons.

To consume 0.05 ppm phosphate, you'd use 14 mL. I'd use that each day.

 

[Jake Martensen]

The math has an issue, making you go more slowly, but that 's OK.

I said:

Let's pick a dosing volume of 1 mL, so we are dosing 6.7 mg of lanthanum, which will remove 6.7 x 0.68 = 4.6 mg of phosphate.

If that is added to an aquarium that has a total volume of 100 L, then we will be expecting to remove about 4.6 mg/100 L = 0.046 mg/L (~0.047 ppm) of phosphate.

But you calculated per 100 gallons.

To consume 0.05 ppm phosphate, you'd use 14 mL. I'd use that each day.

So glad I asked you to check my math! Thanks again and I will let you know how it goes. Have a great weekend!

 

[areefer01]

So glad I asked you to check my math! Thanks again and I will let you know how it goes. Have a great weekend!

I believe that RHF has a rule here somewhere that is along the lines of 'it always coming down to math' or some colorful (not cussing) verbiage along those lines :)

 

[Jake Martensen]

good afternoon. I order the lanthanum and it is crystal form. Is this right? Got it on amazon - Lanthanum Chloride Heptahydrate by Chemsavers.
I was expecting a powder but have nothing to base that off of.
Thanks!!

 

[Randy Holmes-Farley]

good afternoon. I order the lanthanum and it is crystal form. Is this right? Got it on amazon - Lanthanum Chloride Heptahydrate by Chemsavers.
I was expecting a powder but have nothing to base that off of.
Thanks!!

I’ve not seen the forms available, but there’s nothing wrong with crystals. In some cases, where recrystallization is used as a form of purification, it may be better than an amorphous powder. :)

 

[Fasthandsslowmind]

I'm thinking I'll give Lanthanum dosing a try. Ordered Chemsavers:

Lanthanum Chloride Heptahydrate, AR Grade, 99.95+%, 25g​

from Amazon. I think my best bet is to create a solution that allows for a continuous drip into the skimmer. My PO4 reads a steady 0.42ish ppm for the last few months, and I think there's quite a bit bound in the rock.


I'll do the math, but to double check, can someone give their idea of a safe continuous dose (in approx 100ml/day) via a peristaltic pump (Ecotec Versa). I'll definitely start VERY slow with.a minimum effective dose. Total tank volume is around 900 liters.

Thanks!!!

 

[Mickey]

I can tell you what I've been doing for about a year now. I use Randy's formula of 9 gms in 500ml and then further dilute it with another 1500ml to make a 2000 ml solution. then I drip slowly into the sump. I don't drip into the skimmer but it does go into the skimmer compartment. I do not use filter socks. I've seen no adverse reactions. My system is about 240 total gallons and I typically dose 75-125 ml per day over a 24 hour period. Dosage depends on whether my phosphate level is heading up or down. Phosphate level started well over 1.50 (yes, that is over 1.00) and tank has been set up for over 20 years so there's lots of phosphate bound up in the rocks. Level right now is around .30.

Good luck.

 

[Fasthandsslowmind]

Outstanding, thank you!

Another question:

Is a ReefMat generally considered sufficient for removing the flocculent? Seems like it does the same thing as a filter sock, but better.

 

[gbroadbridge]

Outstanding, thank you!

Another question:

Is a ReefMat generally considered sufficient for removing the flocculent? Seems like it does the same thing as a filter sock, but better.

I think the RS reefmat is 100 micron - you really need much finer than that to catch the lanthanum phosphate precipitate. Most folks use 5 micron socks.

I know that my roller mat which uses 25 micron material does not filter enough as the tank went slightly milky when I tried.

 

[Mickey]

Outstanding, thank you!

Another question:

Is a ReefMat generally considered sufficient for removing the flocculent? Seems like it does the same thing as a filter sock, but better.

I can't answer that one as I don't use filter socks or a ReefMat. I've had no problems in the tank and fish have been unaffected and I think that's because I use it so diluted and I dose it over 24 hours. As groadbridge said above, I believe those who do use it with a filter generally use a 5 micron.

 

[Fasthandsslowmind]

Strange. Do you think that all the precipitate is removed by skimming in your system?

 

[Mickey]

I really have no idea. I dose it so slowly and so diluted that I never see any clouding or anything. I have noticed that my water sample test results do show some lanthanum in the water, which isn't a surprise.

 

[areefer01]

Strange. Do you think that all the precipitate is removed by skimming in your system?

As they mentioned earlier, they are taking RHF recipe and diluting it further. Final product then is slowly dosed over X period of time which is several hours in their case.

If you wanted to do something similar you could make up RHF recipe, collect a cup of your displays water, and manually add a drop to see what effect it has on the water. You could then dilute that and repeat. Having used a similar RHF blend and doing similar I clearly see the cloudiness which is why fellow hobbyist recommend using a 10 micron filter sock and the entry point. This then is typically in front of the skimmer intake.

Safety in numbers.

 

[Mickey]

It's time to reorder my lanthanum chloride. I've been using the Chemsavers 100 gm from A for around $65. In looking it up there is now another option that is significantly cheaper at 500 gms for $100 but not a lot of information and it's coming from China. Not sure where Chemsavers comes from.

@Randy Holmes-Farley - do you think this is okay?

Amazon.com

Here's the description: Name Lanthanum chloride heptahydrate Synonyms Lanthanum chloride lanthanum trichloride Lanthanum chloride, hydrated lanthanum chloride crystalline Lanthanum chloride heptahydrate LANTHANUM CHLORIDE-7-HYDRATE R. G. LanthanumchloridehydrateREOwhitextl CAS 10025-84-0 EINECS 640-503-8 InChI InChI=1/ClH.La.7H2O/h1H;;7*1H2/q;+3;;;;;; 10025-84-0 - Physico-chemical Properties Molecular Formula Cl3H14LaO7 Molar Mass 371.37

The Chemsavers is advertised as AR grade, this one doesn't say that. It does say 99.99% Metals Basis but not sure what that means.

 

[Jasonak]

It's time to reorder my lanthanum chloride. I've been using the Chemsavers 100 gm from A for around $65. In looking it up there is now another option that is significantly cheaper at 500 gms for $100 but not a lot of information and it's coming from China. Not sure where Chemsavers comes from.

@Randy Holmes-Farley - do you think this is okay?

Amazon.com

Here's the description: Name Lanthanum chloride heptahydrate Synonyms Lanthanum chloride lanthanum trichloride Lanthanum chloride, hydrated lanthanum chloride crystalline Lanthanum chloride heptahydrate LANTHANUM CHLORIDE-7-HYDRATE R. G. LanthanumchloridehydrateREOwhitextl CAS 10025-84-0 EINECS 640-503-8 InChI InChI=1/ClH.La.7H2O/h1H;;7*1H2/q;+3;;;;;; 10025-84-0 - Physico-chemical Properties Molecular Formula Cl3H14LaO7 Molar Mass 371.37

The Chemsavers is advertised as AR grade, this one doesn't say that. It does say 99.99% Metals Basis but not sure what that means.

What did you find out about this ? Ive been using tropic marin liquid elimi phos and just ran out and was going to make my own so was searching for a source of Lanthanum

 

[Mickey]

I never heard back from Randy so I went ahead and just reordered from Chemsavers as I didn't want to take a chance. The one I linked to is signficantly less expensive but it comes from China and seller is a company I never heard of. So I decided to stick with what I now works well.

If you decide to try another source, let me know how it goes.

Also, just an FYI - the Chemsaver product is in crystal form and slightly damp so sticks together. Doesn't give me any problems but I've seen some posts or maybe it was Amazon reviews complaining that it isn't a powder.

 

[Jasonak]

Chemsaver

I didnt see chemsaver on Amazon you buy it from ebay ?