Liquid PO4 Removers

[isjg]

For those wondering what these do, here's a series of pics I took when experimenting with a Lanthanum based PO4 remover last year. The one I used was Starver, principally for swimming pool use but stated to be suitable for aquaria. The formulation of this particular product is 133g\l Lanthanum glycolate hexahydrate. Other La products may be La Carbonate, La Chloride, La Sulphate and one I know of is a blend of these. I can't comment on the merits of one over the other as I haven't tested them.

Other liquid phosphate removers available are usually iron based when for aquarium use. Other metals like magnesium, calcium or strontium have also been used in the water and wastewater industry although I know of at least one aquarium PO4 remover product that was based on Strontium (NatuReef Phosphagone).

They are designed to precipitate the phosphate rather than using adsorption like GFOs, resins etc. This precipitate needs to be removed in order to remove the phosphate from the system. Removal is through mechanical means like filtering, skimming etc.

These pics show the various stages of this precipitate under trial conditions. I used old tank water with pH 8.0, alkalinity 9dkh and phosphate 3ppm. (This extremely high PO4 was why I was doing these experiments. Other media just couldn't handle it)

To test extreme conditions I overdosed with 25ml of product into 500ml of water and mixed well.

Initial dosing -

After 1 hour -

After 2 hours -

After 4 hours -

The next day -

I didn't do intermediate water tests but the final measurements when I tested the next day were Phosphate unmeasurable, alkalinity 6dkh and pH below my test kit limit of 7.5 The alkalinity drop is due to the precipitation of carbonate as Lanthanum Carbonate. It's easy to see from this that maintaining alkalinity is very important when using these lanthanides. This is usually stated on the bottle. This sharp drop could be the reason why some of these products have been known to adversely affect sensitive livestock, particularly yellow tangs. Personally I have been using it for around a year without issue, and I have a yellow tang.

I hope this provides a little clarity on what these do but I can't offer advice on how to use them in individual situations as there are too many variables. Any attempt at using them is entirely at your own risk and I would stress that extreme care be taken when attempting to use them until the effects in your particular case can be determined. In all cases slow and steady would be the best approach.

cheers

 

[Billybeau1]

That looks like a Ca++ snowstorm to me.

I tried a liquid PO4 remover once and it did not have any affect on my PO4 level after a one month treatment per instructions. All it did was make my skimmer go nuts and throw my chemistry out of balance.

Also, I have not seen an iron based liquid PO4 remover here in the States. Maybe I just haven't noticed.

 

[isjg]

It was a big overdose so a lot would have precipitated out. Did get rid of all the phosphate though.

As for liquid iron based removers, Salifert have one.

I don't know which liquid remover you tried, but I haven't seen much effect on skimmer operation with this one.

 

[boxfishpooalot]

Mine does the same thing(PHOS free) and contains La Sulphate, La Chloride. But Im thinking of switching brands because inverts definitely are irritated by the flock, almost stunned.

However, this stuff is very potent! Helped me also with 3ppm Po4 reduction. Instantly gone and finally corraline is starting to grow in my fo again.

But it needs to be dosed daily in my tank. Im wondering if it will grab phosphate without having to use up alkalinity at the same time, or does it just grab one or the other?

 

[Billybeau1]

I tried the Korallin brand (I think thats how its spelled.) Made in Germany I believe.

I was not aware that Saliferts PO4 liquid was iron based. I'll have to ask Habib about this.

 

[isjg]

The Korallin PO4 Minus is La Chloride afaik. From memory RHF said (in a thread here somewhere) if one was to use a lanthanide, that the carbonate would be better than the chloride. I don't recall the exact reason, possibly due to it forming La carbonate before it forms La phosphate. (as does La Sulphate) ie if you add the carbonate to start with there's less impact on alk.
In anycase, I contacted the Starver manufacturer to query their formula change from La carbonate to La Glycolate Hexahydrate and they reckoned it was just as safe, had the same effect and was just a new and improved version.
This patent application goes into great detail about the various effects of lanthanides in different forms and why this new La Glycolate Hexahydrate formula is better.

http://www.patentstorm.us/patents/6846432-description.html

Found this in there where it confirms what I was saying above -

"a significant proportion of the lanthanum chloride reacts with dissolved carbonate and that the second-stage conversion of the carbonate to the phosphate takes place at a much lower rate than the direct reaction of the lanthanum chloride with the dissolved phosphate because the lanthanum carbonate is taken out of solution. Further, the rate of formation of particles of lanthanum carbonate and phosphate large enough to be removed by filtration is slow."

 

[cthetoy]

Would low pH cause the phosphate to precipate back out? Im using a Calcium reactor and was worried if the 6.5 pH will cause my phosphates to precipate out in the reactor

 

[isjg]

Yes, low pH will cause it to break down again. The question is at what point? I've heard varying figures from 5 to 6. So 6.5 might be a problem.

However, having said that, it would only be a problem for the lanthanum (iron or whatever) phosphate that actually made it into the reactor. The idea of these treatments is to mechanically remove it as soon as possible. You could put filters, socks, skimmer etc before the reactor to catch it before it went in.

In any case, whatever was broken down would simply recombine again once it reached an area with higher pH.