Cali Kid Corals

Guide: Lanthanum Chloride dosing for Phosphate control

@JVU is correct, the stuff sold for the hobby is a variety of concentrations - so be careful just blindly copying formulas, I linked a handy calculator in the original post.

@Ayman I have not drilled my skimmer yet, running the tube through the top still like in the pic. It’s really such a minor thing it hasn’t bugged me enough to inspire drilling yet.

@L/B Block that’s a cool method and glad to hear the process is working for you. It’s really the best way to manage phosphates, by far. I am curious to see how the tube / pump do over time - I’m still hesitant to run the stuff through the pump. The precipitate likes to stick and cling to stuff, which is the concern I have.
 
@JVU is correct, the stuff sold for the hobby is a variety of concentrations - so be careful just blindly copying formulas, I linked a handy calculator in the original post.

@Ayman I have not drilled my skimmer yet, running the tube through the top still like in the pic. It’s really such a minor thing it hasn’t bugged me enough to inspire drilling yet.

@L/B Block that’s a cool method and glad to hear the process is working for you. It’s really the best way to manage phosphates, by far. I am curious to see how the tube / pump do over time - I’m still hesitant to run the stuff through the pump. The precipitate likes to stick and cling to stuff, which is the concern I have.
@derek_SR- will see what happens over time. I def understand the concern when dosing it undiluted as I was seeing huge white specks in the skimmate.. I only did that temporarily to get a base dose and then knew how much to dilute it by
diluted not so -and hopefully that bypasses the “stickiness”. Skimmer is way overdue for a good cleaning (like it’s never been) so perhaps I’ll do that much sooner than later!

Otherwise really liking the method - really is the most effective way of managing PO4 in a consistent way in my view.
 
I am interested in doing this. Read some posts before about tangs being sensitive to this. Have you had any issues? I have a gem and a purple I don’t want to put at risk.
 
I am interested in doing this. Read some posts before about tangs being sensitive to this. Have you had any issues? I have a gem and a purple I don’t want to put at risk.
Risk is low - most reported issues seems to be with yellow tangs in particular. A lot of people dose directly into their DT without any filtration with no issues.

Remember that the LaCl binds with Po4 to form a particulate - which, if filtered via skimmer or sock, never really enters the water column. Where you can get into trouble is some combination of these factors - not enough po4 (so the lacl gets loose in the water, overdosing, and/or not filtering.
 
Risk is low - most reported issues seems to be with yellow tangs in particular. A lot of people dose directly into their DT without any filtration with no issues.

Remember that the LaCl binds with Po4 to form a particulate - which, if filtered via skimmer or sock, never really enters the water column. Where you can get into trouble is some combination of these factors - not enough po4 (so the lacl gets loose in the water, overdosing, and/or not filtering.
Safest thing would be to have the skimmer outflow pipe into a filter sock then right? The academy does theirs into the sand filters which get back flushed during water changes, so similar method.
 
Safest thing would be to have the skimmer outflow pipe into a filter sock then right? The academy does theirs into the sand filters which get back flushed during water changes, so similar method.
Until this filter sock under water in the back of your sump clogs… then super not safe

Also, as it clogs it will decrease outflow and after cleaning will increase outflow. The way we modulate the skimmer function on most skimmers is by gating this outflow. So with a constantly changing outflow resistance it will always be unstable.
 
I’ve done the 10 micron filter sock. It gets clogged really fast. I bought 3 sock and figured I could rotate them out. It got old really fast. As time goes on. The socks get clogged faster. Now I inject the dose into the connection pipe between the skimmer body and the pump. Hose is cut at a 45* angle. Back faces the pump. I still have to clean the dose pipe once in a while for build up.
 
Safest thing would be to have the skimmer outflow pipe into a filter sock then right? The academy does theirs into the sand filters which get back flushed during water changes, so similar method.

The particulate should all get skimmed out, I don’t think an additional filter sock is necessary. I’ve never seen lanthanum show on an ICP other than an accidental overdose event (when the skimmer was off).
 
This is why I like dosing LaCl-
I keep it steady at at around .18-.19.
I have been tracking it over last few weeks.

The ratio is NO3/PO4 *1.53 after Charles talk few weeks back at HTA although I was doing this before.

The SPS, across, my euphillya seem to enjoy the lower PO4 a bit. Birds nest is taking off like crazy. NO3 is a bit all over but is fine..
 

Attachments

  • IMG_0871.png
    IMG_0871.png
    36.2 KB · Views: 50
Just wanted to comment on the ratios I see being mentioned on the forum. Just to clarify the formula of NO3/PO4 * 1.53 does not give a ratio of NO3/PO4 but of N/P. So if you are adding NH4 this is a source of N as is NO3 and NO2. Normally NH4 is undetectable in aquaria as it is quickly utilized by bacteria, algae and by anything with zooxanthellae. So if you switch to NH4 dosing, then you will no longer be able to calculate an accurate N/P ratio as you won't be able to measure the N you are adding from it, but you will still see NO3 values.
 
Last edited:
Ok for those who are doing this-do you regularly run ICP tests to see if there is a build up? I was a little surprised to see a 3.x value for LaCl. Obviously I cut back and changed the dosing regimen from 3x at 14.x ml to 10x at 4 ml.
 
Ok for those who are doing this-do you regularly run ICP tests to see if there is a build up? I was a little surprised to see a 3.x value for LaCl. Obviously I cut back and changed the dosing regimen from 3x at 14.x ml to 10x at 4 ml.
In my experience, and granted this is on a 212,000 gallon system, you need to add it slowly, in small amounts. We add ours into a sand filter inlet to remove the precipitate. We are adding 275 mL diluted into 30 gallons of DI water of which we currently are dosing approx. 3 gallons/24 hrs. So basically 27 mL per 24 hrs of LC. You are adding almost twice that into a much much smaller volume. We run our PO4 between 0.6 and 0.7 ppm currently due to having a nitrate value of 42 ppm. I have never measured La in this system using FM ICP. But the few times I have done ICP testing on our 95,000 gallon cold water system system to which we add 380 mL to 30 gallons of DI water, and we dose approx. 4 gallons a day also into a sand filter I have seen La in the water: 5.2 ppb in October and 4.2 ppb in January, both of which were within the acceptable Fauna Marin range of 2-10 ppb. So your values of 3.x does not seem out of line with that range.

There are two possible reasons that La is being detected: it is free LaCl3 that has not reacted with PO4 or it is LaPO4 or La2(CO3)3 precipitate that has gotten past your filtration method you are using to remove the precipitate. ICP testing cannot distinguish between these due to the nature of the methodology i.e. high temp plasma flame combusting everything into their elemental constituents.
 
Last edited:
In my experience, and granted this is on a 212,000 gallon system, you need to add it slowly, in small amounts. We add ours into a sand filter inlet to remove the precipitate. We are adding 275 mL diluted into 30 gallons of DI water of which we currently are dosing approx. 3 gallons/24 hrs. So basically 27 mL per 24 hrs of LC. You are adding almost twice that into a much much smaller volume. We run out PO4 between 0.6 and 0.7 ppm currently due to having a nitrate value of 42 ppm. I have never measured La in this system using FM ICP. But the few times I have done ICP testing on our 95,000 gallon cold water system system to which we add 380 mL to 30 gallons of DI water, and we dose approx. 4 gallons a day also into a sand filter I have seen La in the water: 5.2 ppb in October and 4.2 ppb in January, both of which were within the acceptable Fauna Marin range of 2-10 ppb. So your values of 3.x does not seem out of line with that range.

There are two possible reasons that La is being detected: it is free La that has not reacted with PO4 or it is LaPO4 or LaCO3 precipitate that has gotten past your filtration method you are using to remove the precipitate. ICP testing cannot distinguish between these due to the nature of the methodology i.e. high temp plasma flame combusting everything into their elemental constituents.
Thanks. This is helpful. Def will change the dosing regimen. As I dose into the protein skimmer I limit it to night time when it doesn’t get stopped for feedings. But I can expand the time frame. Also sounds like I need to dilute even more (40:1) - I tend to keep it around .2 (for nitrates around 5)
 
The ability to remove the precipitate (either LaPO4 or La2(CO3)3) is entirely dependent on contact time and the size of particulate your skimmer can remove. If your contact time is too short and the resulting particulate too small for your filter to remove, it will get back into the tank. I would recommend adding a sock filter to the effluent of the skimmer, 10 micron maybe?

You should read this article that describes some work down on the ability of a sand filter to remove La precipitates, and the effects of contact time on particulate size and filter dwell time in particulate removal: http://drumandcroaker.org/pdf/2024v2.pdf#page=128.00
 
  • Like
Reactions: JVU
The ability to remove the precipitate (either LaPO4 or La2(CO3)3) is entirely dependent on contact time and the size of particulate your skimmer can remove. If your contact time is too short and the resulting particulate too small for your filter to remove, it will get back into the tank. I would recommend adding a sock filter to the effluent of the skimmer, 10 micron maybe?

You should read this article that describes some work down on the ability of a sand filter to remove La precipitates, and the effects of contact time on particulate size and filter dwell time in particulate removal: http://drumandcroaker.org/pdf/2024v2.pdf#page=128.00


I will def give this a read! Thank you. Quite the interesting journal.
 
Ok for those who are doing this-do you regularly run ICP tests to see if there is a build up? I was a little surprised to see a 3.x value for LaCl. Obviously I cut back and changed the dosing regimen from 3x at 14.x ml to 10x at 4 ml.
The biggest problem I see that people dose lanth in the skimmer have is being too agressive on the dose. If you are too agressive one the dose, you up the chance that you will get lanth that hasn't reacted going outside of the skimmer body. Start way low and bring it up slowly. :D
 
The biggest problem I see that people dose lanth in the skimmer have is being too agressive on the dose. If you are too agressive one the dose, you up the chance that you will get lanth that hasn't reacted going outside of the skimmer body. Start way low and bring it up slowly. :D
Ooops. That’s me. I’d thought I was going slow. But not slow enough. Just did cut the dose though in addition to changing dosing frequency so hopefully less escapes the skimmer and more precipitates out as waste in the skimmer cup.
 
Back
Top