Lanthanum Chloride - recommended micron size?

[r0cksteady]

Hi All,

Ive started dosing Lanthanum Chloride into my skimmer chamber with a 200 micron filter bag and am just wondering if this is sufficient or if I should go down to a 100 micron or smaller? Also are the mesh bags acceptable or should I be using the fibre\felt ones?

Any help would be appreciated.

 

[HighlandReefer]

When you add Lanthanum chloride to a smaller volume of water only so much phosphate is in that amount of water to precipitate out. Extra LC will go into your tank and then react with phosphate in the larger volume of water. I'm not sure if adding LC to a skimmer is a good method. Perhaps dripping smaller amounts and allowing proper mixture for the LC to react with the available phosphate in the given water volume is better.

As far as filter pore size, the smaller the better. Scientific experiments show 0.45 micron filters work the best. Boomer recommends a 10 micron filter, which I would not go larger, as it will still miss some of the precipitates.

This article may be of interest:

Lanthanum chloride or lanthanum carboxylate for orthophosphate
removal in seawater aquarium - a feasibility study
YING ZHANG; KAR SONG WONG
http://aalso.org/2009presentations/ZhangWongOrthophosphateRemovalPaper.pdf

 

[r0cksteady]

Thank you for the response and links.

How important is it for the filter sock to be out of the water? ie can the bottom half of it be submerged whilst the top half is out of the water but with the overflow going into it?

 

[HighlandReefer]

I would think it would be ok as long as the filter sock is not allowed to overflow. The smaller pore size bags will clog with debris quickly.

The bottom line is, you don't want to see the water clouding in your tank.

 

[Boomer]

Cliff finally somebody, YOU, for a real a answer I have been telling some lately try 5 microns. I think 0.45 is pushing things to far and will plug up really fast. A submicron, <1 mciron filter "Cold Sterilizes" water.

Scientific experiments show 0.45 micron filters work the best:bounce1:

 

[HighlandReefer]

I would think a series of filters starting with perhaps 75 microns and then get progressively smaller, may be the best answer for maintenance & safety. Certainly a 0.45 micron filter is a bit much as you have stated.

Personally, I would only think about using LC in a very large system where money becomes a big factor. For a regular size system, GFO would be the way to go IMHO.

 

[stormrider27]

I'm using Lanthanum Chloride to pull the PO4 out of my dead rock prior to seeding. I have the rock in a Rubbermaid tub with 30 gal. of RO, a powerhead and a heater. Should I be using a filter sock? In the past two weeks the PO4 reading has dropped from .29 to .12 according to my Hanna.

Thanks!
Mark

 

[HighlandReefer]

Just for reference, some of the smaller fish (I have only researched one small freshwater fish) have gill structures that will filter out particles down to around 10 microns in size (they state <10 microns). It seems that the concern is that the precipitates can lodge in the fish gill structures. A 5 micron filter bag may be better for small fish.

Regulation of diurnal filter feeding by a novel gill structure in Amblypharyngodon melettinus (Teleostei, Cyprinidae)
http://www.springerlink.com/content/2gc748a7a3l23hq7/

 

[Gary Majchrzak]

JMO: I would definitely use a filter sock (or other type of mechanical filter) while dosing (dilute) lanthanum chloride. I use a 10 micron filter.


here's a thread on my method

 

[HighlandReefer]

I'm using Lanthanum Chloride to pull the PO4 out of my dead rock prior to seeding. I have the rock in a Rubbermaid tub with 30 gal. of RO, a powerhead and a heater. Should I be using a filter sock? In the past two weeks the PO4 reading has dropped from .29 to .12 according to my Hanna.

Thanks!
Mark

I would think if you rinse the rock in clean water several times to help remove any precipitants this would work.

I guess we can get carried away with too much concern regarding the LC precipitates. There are other precipitants found in our tanks as well which don't dissolve like calcium carbonate that can pose problems as well and fish seem to survive precipitation events in most cases. LC precipitant water clouding is not good in any case.

 

[UVvis]

With lanthanum precipitates in the water, it can clog up filters quickly. The good part is that it helps pull more particulat matter out of the water as it clogs. Several products have lanthanum salts sold as filtration aids/clarifiers. Most larger systems that use these inject the lanthanum in filter return lines to give it time to react. The dirtier the filter gets, the more effective it is at pulling out more particles. The downside is that it reduced flow.

 

[HighlandReefer]

UVvis,

What size precipitants do the big boys filter down to or what size filter would you recommend?

 

[UVvis]

Depending on the sand bed (type, condition, volume, height) a high pressure sand filter at optimal conditions is probably around a 5-10 micron filter. Lanthanum precipitates will allow the bed, as it gets dirty, to work at 2 micron, or finer.

Filtration has two important parts, pore size and flow rate. Everyone seems to latch onto the pore size, and ignore the flow rate. Smaller filter pores usually mean reduced flow.

My honest recommendation, is to go with the finest filter pore size you can without letting the flow rate suffer. Anything under 20 micron should start to be able to pull out lanthanum precipitates, and letting the filter go longer and longer will dirty the filter and allow more and finer particle entrapment.

Since most sumps aren't set up for a progressively smaller and smaller micron filter to do a full polish in one pass, I'd dirty up a sock as best as possible before adding lanthanum, and use the finest filter you can get by with to maintain your system flow. Lanthanum precipitates are somewhat dense and will settle out over time.

 

[Gary Majchrzak]

Anything under 20 micron should start to be able to pull out lanthanum precipitates, and letting the filter go longer and longer will dirty the filter and allow more and finer particle entrapment.

this is exactly why I chose to run a 10 micron sock 24/7 nowadays

Since most sumps aren't set up for a progressively smaller and smaller micron filter to do a full polish in one pass, I'd dirty up a sock as best as possible before adding lanthanum, and use the finest filter you can get by with to maintain your system flow. Lanthanum precipitates are somewhat dense and will settle out over time.

I'm in full agreement except for one recommendation: don't start treatment with a dirty sock- start with a clean 10 micron sock. And change it out for another clean 10 micron (or smaller) sock once it's overflowing.

IME it's also a good idea to administer lanthanum chloride during a water change using the 'wet skimmate method' for removing old water from the system.

 

[jason2459]

Depending on the sand bed (type, condition, volume, height) a high pressure sand filter at optimal conditions is probably around a 5-10 micron filter. Lanthanum precipitates will allow the bed, as it gets dirty, to work at 2 micron, or finer.

Filtration has two important parts, pore size and flow rate. Everyone seems to latch onto the pore size, and ignore the flow rate. Smaller filter pores usually mean reduced flow.

My honest recommendation, is to go with the finest filter pore size you can without letting the flow rate suffer. Anything under 20 micron should start to be able to pull out lanthanum precipitates, and letting the filter go longer and longer will dirty the filter and allow more and finer particle entrapment.

Since most sumps aren't set up for a progressively smaller and smaller micron filter to do a full polish in one pass, I'd dirty up a sock as best as possible before adding lanthanum, and use the finest filter you can get by with to maintain your system flow. Lanthanum precipitates are somewhat dense and will settle out over time.

From this it sounds like a Diatom filter is perfect as it gets down to 1micron I believe and has a decent flow rate. I might try this out next time I have a PO4 problem with my vortex xl diatom filter.

 

[Gary Majchrzak]

great point:

great point:

Lanthanum precipitates are somewhat dense and will settle out over time.

often overlooked!

Settling can even occur in a display tank and/or sump.

 

[UVvis]

From this it sounds like a Diatom filter is perfect as it gets down to 1micron I believe and has a decent flow rate. I might try this out next time I have a PO4 problem with my vortex xl diatom filter.

DE is about perfect, but you have the health aspects of the DE to deal with, and DE is a polishing filter agent. If you are using lanthanum, take care to not clog up your DE filter.

Good point Gary. If you are starting with a finer micron sock, no need to dirty it, as it will foul up fast. I was thinking for someone that doesn't have a finer sock available, to just start out with the sock dirty to get the most out of it. Clogging and overflowing means your filter is at capacity.

 

[Gary Majchrzak]

just before it's overflowing

just before it's overflowing

is when a filter sock is working the best so let 'em gunk up real good before changing it out.

The 10 micron bags I use are poly and not readily available in aquarium supply places. They are used in the medical field for dialysis etc.

Note the potential hazards of dosing LaCl3 into a reef aquarium: alkalinity may be depleted and Tridacna clams might suffer to varying degrees.

simple progressive filter arrangement

 

[r0cksteady]

Thanks guys for all the info.

A few questions outside of micron size. Does the material matter ie. mesh bags vs fabric bags?

Also how important is it to dilute the solution as Ive just been squirting 5ml each day into my skimmer chamber which is then caught by my 200micron fabric filter sock. Is this a problem?

Is there a limit to how much you can add at one time? Can I dose 50ml leave it there for a day and then change the filter sock if I have a large ammount of P04?

 

[chicken]

Jason, It is very important to dilute it. If you do not, only some of the Lanthanum Chloride will be used up in the skimmer as there is only so much Po4 available to react with it. The rest will go right through the filter sock and then react with available Po4 that is in the sump or display tank. A 5-10 micron filter sock will only be able to filter out the combined precipitate. I use the SeaKlear Aquaria Phosphate Remover and dilute it in a 2.5g drip doser. I use 1.5ml of it per 100g of system water @ 1ppm of Po4 that needs to be removed. It is extremely important to dose slowly and never over dose. I typically shoot to get my Po4 on my larger FOWLR system down to about 0.1 and then use GFO to get it as close to 0 as possible.