Desorbing phosphate from sand with lanthanum.

[Garf]

Along with phosphate and yellowing compounds, I'm wondering if I'm removing other things when regenerating this sand. Iodate, iron, manganese perhaps? Any insight @taricha @Randy Holmes-Farley please. Tank phosphate now at 0.2ppm (Hanna)

 

[taricha]

If you remove significant yellowing compounds, you are removing some iron.
On GFO, PO4 and Si both attach to the sites, so I'd guess Si might also attach a bit to aragonite too.

 

[Randy Holmes-Farley Verified Community Expert]

Iodate won't bind to calcium carbonate surfaces. Iron and manganese may.

 

[Randy Holmes-Farley Verified Community Expert]

If you remove significant yellowing compounds, you are removing some iron.
On GFO, PO4 and Si both attach to the sites, so I'd guess Si might also attach a bit to aragonite too.

Couldn't the yellowing be organics?

 

[taricha]

Couldn't the yellowing be organics?

Right. Yellow organics in tank water has an absorbance/fluorescence profile that's a pretty good match for what's measured in marine humic substances. So I'm expecting some part of our yellow compounds also likes to grab Fe.

 

[Randy Holmes-Farley Verified Community Expert]

Right. Yellow organics in tank water has an absorbance/fluorescence profile that's a pretty good match for what's measured in marine humic substances. So I'm expecting some part of our yellow compounds also likes to grab Fe.

Ah, OK, I thought since you meant that iron was itself causing the color.

 

[Garf]

Tank phosphate now at 0.15, nitrate at 10ish (salifert). I'll add a pic of the regeneration bucket after giving the regenerated sand a dang good massage;

Edit - I would add that nitrates have taken a nose dive since adding manganese, iodine and iron. Related? I am adding a little more vinegar in my kalk now, however. Maybe still related? Another edit - and double the amount of sand, lol.

 

[Dburr1014]

Tank phosphate now at 0.15, nitrate at 10ish (salifert). I'll add a pic of the regeneration bucket after giving the regenerated sand a dang good massage;

Edit - I would add that nitrates have taken a nose dive since adding manganese, iodine and iron. Related? I am adding a little more vinegar in my kalk now, however. Maybe still related? Another edit - and double the amount of sand, lol.

@Garf are you still doing this test?

I have run into a rapid po4 climb myself and I'm thinking it might be because I removed about 15ish lbs of arragonite sand from my system. (not sure exactly on weight) in the past month I went from 0.1ish (forever ran there) to 3.8 today. Last Monday it was 2.8
I first thought testing error but now I don't think so. I'm using a Hanna tester.
The only other change in my system is dosing ammonium chloride as I was zero nitrates since last May. Now I'm about 7.9 days the Hanna tester. It was up to 11pm and I was getting some funky green floating algae in the sump. Actually, I think it was some form of cyanobacteria. I dialed back the AC dose and the cyano is subsiding.
I'm thinking I may put the sand back in and see if po4 drops again. It was basically a remote dsb in the refuge at about 5 inches deep.
I'm finding this type of po4 reduction pretty interesting.

 

[Garf]

@Garf are you still doing this test?

I have run into a rapid po4 climb myself and I'm thinking it might be because I removed about 15ish lbs of arragonite sand from my system. (not sure exactly on weight) in the past month I went from 0.1ish (forever ran there) to 3.8 today. Last Monday it was 2.8
I first thought testing error but now I don't think so. I'm using a Hanna tester.
The only other change in my system is dosing ammonium chloride as I was zero nitrates since last May. Now I'm about 7.9 days the Hanna tester. It was up to 11pm and I was getting some funky green floating algae in the sump. Actually, I think it was some form of cyanobacteria. I dialed back the AC dose and the cyano is subsiding.
I'm thinking I may put the sand back in and see if po4 drops again. It was basically a remote dsb in the refuge.
I'm finding this type of po4 reduction pretty interesting.

Yes, this is the method I'm sticking with, works well for me. Started doing it in the wife's tank also. I would add that in a tank with loads of sand already in the system, progress maybe painfully slow due to the amount of phosphate already bound to that sand.

in the past month I went from 0.1ish (forever ran there) to 3.8 today. Last Monday it was 2.8

Sounds a bit odd. Remote deep sand beds are generally for nitrate control as the sand is left in situ for prolonged periods. I can't think of any process that would increase your phosphates like that, apart from dumping loads of food in, or a phosphate solution, sorry.

 

[Dburr1014]

Sounds a bit odd. Remote deep sand beds are generally for nitrate control as the sand is left in situ for prolonged periods. I can't think of any process that would increase your phosphates like that, apart from dumping loads of food in, or a phosphate solution, sorry.

I did have a auto feeder on the system feeding flakes 4 times a day. I have since removed that. I realize that the sand is for nitrate control and I was trying to get rid of mine. I thought that maybe the sand was also reducing phosphates a little bit. I also tested a new batch of salt water thinking it was in my well, that was 0.02 on the Hanna.
I can't think of anywhere else it's coming from.

 

[Garf]

Update - the wifes tanks phosphate had elevated to 0.8ppm (4 to 5 feedings daily). The tank previously was dosed directly with lanthanum but wanted a tang so employed my sand bag method, which have there own separate regeneration bucket to mine. Unlike my tank she has a skimmer and a sock. A couple of months after adding a lanthanum regenerated sand bag and it's down to 0.17ppm (Hanna). She changes the bag out religiously every 7 days, 3kgs, in a 240 litre tank, bare bottom.

 

[Dburr1014]

Update - the wifes tanks phosphate had elevated to 0.8ppm (4 to 5 feedings daily). The tank previously was dosed directly with lanthanum but wanted a tang so employed my sand bag method, which have there own separate regeneration bucket to mine. Unlike my tank she has a skimmer and a sock. A couple of months after adding a lanthanum regenerated sand bag and it's down to 0.17ppm (Hanna). She changes the bag out religiously every 7 days, 3kgs, in a 240 litre tank, bare bottom.

Can you share your pics of the whole process?
I'm steadily climbing, 0.4 right now. I just added 30#'s of new sand and a rock that's probably 15ish pounds. Still climbing.

 

[Randy Holmes-Farley Verified Community Expert]

Update - the wifes tanks phosphate had elevated to 0.8ppm (4 to 5 feedings daily). The tank previously was dosed directly with lanthanum but wanted a tang so employed my sand bag method, which have there own separate regeneration bucket to mine. Unlike my tank she has a skimmer and a sock. A couple of months after adding a lanthanum regenerated sand bag and it's down to 0.17ppm (Hanna). She changes the bag out religiously every 7 days, 3kgs, in a 240 litre tank, bare bottom.

Thanks for the update!

 

[Garf]

Can you share your pics of the whole process?
I'm steadily climbing, 0.4 right now. I just added 30#'s of new sand and a rock that's probably 15ish pounds. Still climbing.

You don't like GFO? Lol.

It's really very simple.

1) Get a mesh bag and fill it with sand (the more the merrier).
2) Place the bag into a bucket with enough fresh RODI water to fully submerge it, with a tiny circulation pump.
3) Add an amount of lanthanum chloride (I'm using 20 MLS of a solution comprised 10 grammes lanthanum chloride in 500 mls RODI)
4) Allow to regenerate for 3 days (or more).
5) Agitate the bag to remove sludge and remove from bucket, pronto.
6) Rinse in RODI.
7) Allow to drain and put into sump/tank (location appears unimportant)
8) Leave in tank for 3 days or more.
9) Remove from tank and rinse in hot tapwater, let it drain, then repeat from number 2) onwards.

We use 2 bags so that 1 is in the tank whilst the other is in the regeneration bucket. It appears to be a lot of steps but it's very simple really.

I'll add a pic of the wife's regeneration bucket, lol

 

[Miami Reef]

Do you think this method is safer than adding lanthanum directly into a tank?

Do you spread out the lanthanum dose or just dose one shot?

How do you know when the phosphate is completely desorbed?

Is testing phosphate in the regeneration bucket accurate if you dose lanthanum?

I hope I’m not asking repetitive questions.

 

[Miami Reef]

Imagine using the regeneration method with GFO instead of sand. Would the GFO have more surface area than sand to adsorb more PO4?

 

[Garf]

Do you think this method is safer than adding lanthanum directly into a tank?

Yes, although likely not as efficient.

Do you spread out the lanthanum dose or just dose one shot?

One shot.

How do you know when the phosphate is completely desorbed?

I did some testing early on in my own style that indicated a sand bag with reach equilibrium in 3 days. I actually think it's faster than that but I had absolutely no intention of cleaning it any sooner than that anyhow.

Is testing phosphate in the regeneration bucket accurate if you dose lanthanum?

I've tested zero in regenerated clear water, and high phosphate in the sludge, so I guess so.

I hope I’m not asking repetitive questions.

Nope, I don't recall those questions before.

Imagine using the regeneration method with GFO instead of sand. Would the GFO have more surface area than sand to adsorb more PO4?

I've pondered this also. I got it into my head that GFO gets a coating of calcium carbonate over time, reducing its effectiveness towards that of sand. No idea why I've got that in my head, probably on a googling session, perhaps @Randy Holmes-Farley knows.

 

[Miami Reef]

Yes, although likely not as efficient.

One shot.

I did some testing early on in my own style that indicated a sand bag with reach equilibrium in 3 days. I actually think it's faster than that but I had absolutely no intention of cleaning it any sooner than that anyhow.

I've tested zero in regenerated clear water, and high phosphate in the sludge, so I guess so.

Nope, I don't recall those questions before.

I've pondered this also. I got it into my head that GFO gets a coating of calcium carbonate over time, reducing its effectiveness towards that of sand. No idea why I've got that in my head, probably on a googling session, perhaps @Randy Holmes-Farley knows.

Thank you so much! It’s a very interesting method. Can you explain the story on how you came up with it? Pretty ingenious if you ask me!

 

[Randy Holmes-Farley Verified Community Expert]

Imagine using the regeneration method with GFO instead of sand. Would the GFO have more surface area than sand to adsorb more PO4?

Yes

 

[Garf]

Thank you so much! It’s a very interesting method. Can you explain the story on how you came up with it? Pretty ingenious if you ask me!

I'm trying to cement my name in reefing history, perhaps even develope a new science, lol