Couple quick questions about binding/bound, leaching Phosphates.

[LRT]

Interested to know exactly what this all means. Is this happening because its being used by algae and or bacteria as it attaches to surface areas? Is rock and substrate actually "absorbing" phosphates or a little of all of the above?
I'm asking mainly because I've been cleaning my rock pretty vigorously lately and I'm seeing dramatic reduction in phosphates every time I do it. Simple scrub with brush and rinse in tub with tap water.
Great success stories are being reported with the use of lanthanum chloride reducing phosphates. Ive personally nearly stripped my system of phosphates using chemipure elite.
Are these chemicals basicly doing the same thing and pulling phosphates from surface level or from inside rock or am I totally off here?

 

[Randy Holmes-Farley Verified Community Expert]

Phosphate can reversibly bind to many things, including calcium carbonate (rock and sand) and iron oxide (GFO) surfaces. That means one phosphate ion attaches to the surface, and sits there for a while, then can come off again. The amount bound can be way, way higher than the amount in the water. One reefer measured tens of ppm worth of phosphate on rock in contact with less than 0.2 ppm in the water.

In reality, vast numbers (way higher than trillions) are coming on and off of exposed live rock and sand all the time in a reef tank.

The number stuck to any surface is related to the concentration actually in the bulk water. More in the water drives more onto the surface, and less in the water lets more come off the surface.

Organisms CANNOT use phosphate bound to a surface. They can only consume phosphate that is loose. There may be ways some organisms can help release phosphate from surfaces (such as locally lowering the pH under a mat of cyanobacteria) or locally reducing the phosphate concentration itself to allow more to come off.

Any method of reducing the phosphate in the water will slowly strip phosphate away from surfaces.

 

[Lost in the Sauce]

Should we understand this to mean that when trying to meaningfully lower phosphates in the water (assuming this is the number we care about) the longer your LR and sand have been established, the longer it will take to remove phosphates from the system as the rock and sand will continue to unbind phosphates into the water as that concentration drops?

 

[LRT]

Phosphate can reversibly bind to many things, including calcium carbonate (rock and sand) and iron oxide (GFO) surfaces. That means one phosphate ion attaches to the surface, and sits there for a while, then can come off again. The amount bound can be way, way higher than the amount in the water. One reefer measured tens of ppm worth of phosphate on rock in contact with less than 0.2 ppm in the water.

In reality, vast numbers (way higher than trillions) are coming on and off of exposed live rock and sand all the time in a reef tank.

The number stuck to any surface is related to the concentration actually in the bulk water. More in the water drives more onto the surface, and less in the water lets more come off the surface.

Organisms CANNOT use phosphate bound to a surface. They can only consume phosphate that is loose. There may be ways some organisms can help release phosphate from surfaces (such as locally lowering the pH under a mat of cyanobacteria) or locally reducing the phosphate concentration itself to allow more to come off.

Any method of reducing the phosphate in the water will slowly strip phosphate away from surfaces.

Awesome Randy thanks makes perfect sense to what im seeing. I seen a post of yours the other day that really got me thinking about this.
I did recently deep clean a tank and a bunch of rock. 0 out my detectable phosphates in process. That night I tried to dose Alk(fusion) and it didn't mix like it typically does when it hits the water it usually disperses before being sucked down overflow and mixes in sump. With undetectable phosphates it actually kinda clumped up and sunk to bottom of my overflow box. I'm assuming alk just precipitated from what I read of your post.
I dosed phosphates to around .1 and next day dosed alk and mixed in just like usual.
I'm now hoping I didn't strip to much phosphates by cleaning the rock but I guess I'll be dosing them to keep the balance until things are re established on the surface.

 

[LRT]

Should we understand this to mean that when trying to meaningfully lower phosphates in the water (assuming this is the number we care about) the longer your LR and sand have been established, the longer it will take to remove phosphates from the system as the rock and sand will continue to unbind phosphates into the water as that concentration drops?

I seen a post by @FarmerTy That I believe when he stated when he was using lanthanum he believes it did actually strip phosphates from his rocks and im assuming substrate. Unbelievable high numbers and when the lanthanum usage was ended his phosphates actually stayed stripped immediately after.
I may have some of that wrong but thats what I got post haha.

 

[Randy Holmes-Farley Verified Community Expert]

Should we understand this to mean that when trying to meaningfully lower phosphates in the water (assuming this is the number we care about) the longer your LR and sand have been established, the longer it will take to remove phosphates from the system as the rock and sand will continue to unbind phosphates into the water as that concentration drops?

It's not a time thing, but rather how high of phosphate the rock and sand surfaces were last exposed to. Much of the actual equilibration will be complete in less than a day, with penetration into pores and deeper in a sand bed taking longer.

 

[Randy Holmes-Farley Verified Community Expert]

I seen a post by @FarmerTy That I believe when he stated when he was using lanthanum he believes it did actually strip phosphates from his rocks and im assuming substrate. Unbelievable high numbers and when the lanthanum usage was ended his phosphates actually stayed stripped immediately after.
I may have some of that wrong but thats what I got post haha.

Yes, many people do that. Lanthanum, GFO, aluminum oxide, and water changes can all accomplish it, but lanthanum is cheapest for outside the tank treatment of rock.

 

[Randy Holmes-Farley Verified Community Expert]

Awesome Randy thanks makes perfect sense to what im seeing. I seen a post of yours the other day that really got me thinking about this.
I did recently deep clean a tank and a bunch of rock. 0 out my detectable phosphates in process. That night I tried to dose Alk(fusion) and it didn't mix like it typically does when it hits the water it usually disperses before being sucked down overflow and mixes in sump. With undetectable phosphates it actually kinda clumped up and sunk to bottom of my overflow box. I'm assuming alk just precipitated from what I read of your post.
I dosed phosphates to around .1 and next day dosed alk and mixed in just like usual.
I'm now hoping I didn't strip to much phosphates by cleaning the rock but I guess I'll be dosing them to keep the balance until things are re established on the surface.

It's unlikely you stripped it too much by that process. But dosing phosphate is easy if you did.

 

[LRT]

It's unlikely you stripped it too much by that process. But dosing phosphate is easy if you did.

10-4 i should of mentioned i totally deep cleaned tank. Rocks, all glass surfaces and it is barebottom.
Phosphates didn't show up detectable with salifert directly after cleaning but I know some had to be there.
My Phosphates did stay at .1 the following day.
Im going to check it again today before dosing alk to see what happened and if im seeing a reduction and usage of phosphates.
Here's that tank totally spotless. I went a little overboard lol

 

[Lost in the Sauce]

It's not a time thing, but rather how high of phosphate the rock and sand surfaces were last exposed to. Much of the actual equilibration will be complete in less than a day, with penetration into pores and deeper in a sand bed taking longer.

Is there a point to where short-term saturation is a concern?

In other words, is the transfer of phosphates from the rock and substrate constrained by anything?

If general equilibrium between the two can happen in a day, I assume not. I was told early in my drinking through a fire hose days that phosphates slowly unbind from solids but cannot remember the mechanics of why, as it was stated.

 

[Randy Holmes-Farley Verified Community Expert]

Is there a point to where short-term saturation is a concern?

In other words, is the transfer of phosphates from the rock and substrate constrained by anything?

If general equilibrium between the two can happen in a day, I assume not. I was told early in my drinking through a fire hose days that phosphates slowly unbind from solids but cannot remember the mechanics of why, as it was stated.

It is not at all slow to happen on exposed surfaces (likely takes less than a minute), but it can be slow to reach full equilibrium in a reef tank because many of the surfaces are not readily exposed, but are below the surface of sand or in rock pores where diffusion of phosphate in and out can be slow.

Saturation is not really the way folks ordinarily think of it. The more phosphate is in the water, the more will bind, up to some limit where reefers do not go. It's not like a glass of water filling up. It's more like a river, where the more water you add at the top, the more flows down it, even if it may spread out more and more.

This paper shows a lot of kinetic data on rates of binding of phospathe to aragonite. For comparison on Figure 4, 30 umole/L (30 uM) = 30 umole/L x 95 g/mole = 2,850 ug/L = 2.9 mg/L = 2.9 ppm. So you can see no "saturation" is reached at 2.8 ppm.

Figure 4. Comparison of adsorption of phosphate on aragonite andcalcite...

Download scientific diagram | Comparison of adsorption of phosphate on aragonite andcalcite (2 g L − 1 ) in from publication: Adsorption and Desorption of Phosphate on Calcite and Aragonite in Seawater | The adsorption and desorption of phosphate on calcite and aragonite were investigated as a...

www.researchgate.net

 

[LRT]

It is not at all slow to happen on exposed surfaces (likely takes less than a minute), but it can be slow to reach full equilibrium in a reef tank because many of the surfaces are not readily exposed, but are below the surface of sand or in rock pores where diffusion of phosphate in and out can be slow.

Saturation is not really the way folks ordinarily think of it. The more phosphate is in the water, the more will bind, up to some limit where reefers do not go. It's not like a glass of water filling up. It's more like a river, where the more water you add at the top, the more flows down it, even if it may spread out more and more.

This paper shows a lot of kinetic data on rates of binding of phospathe to aragonite. For comparison on Figure 4, 30 umole/L (30 uM) = 30 umole/L x 95 g/mole = 2,850 ug/L = 2.9 mg/L = 2.9 ppm. So you can see no "saturation" is reached at 2.8 ppm.

Figure 4. Comparison of adsorption of phosphate on aragonite andcalcite...

Download scientific diagram | Comparison of adsorption of phosphate on aragonite andcalcite (2 g L − 1 ) in from publication: Adsorption and Desorption of Phosphate on Calcite and Aragonite in Seawater | The adsorption and desorption of phosphate on calcite and aragonite were investigated as a...

www.researchgate.net

This is very interesting and I'm going to have to read more to let absorb but has me thinking about some of the reefs I've been following(some of the nicest I've seen) with extraordinarily high Phosphate numbers accumulated over most likely years. Im curious if this is where the "old tank syndrome" comes into play and if at a certain point these tanks just simply can't process, absorb or store enough Phosphates without that balance being impacted once max levels are achieved. I wonder if the cure or good practice for some of these older reefs would be to just simply run lanthanum and strip to healthy levels and start process over to help maintain the balance.

 

[Treefer32]

This is very interesting and I'm going to have to read more to let absorb but has me thinking about some of the reefs I've been following(some of the nicest I've seen) with extraordinarily high Phosphate numbers accumulated over most likely years. Im curious if this is where the "old tank syndrome" comes into play and if at a certain point these tanks just simply can't process, absorb or store enough Phosphates without that balance being impacted once max levels are achieved. I wonder if the cure or good practice for some of these older reefs would be to just simply run lanthanum and strip to healthy levels and start process over to help maintain the balance.

I had issues with my corals dying fairly rapidly. Couldn't figure out why, so I sent my water off for an ICP test. The only issue was my phosphates were detected at .56 ppm.

I implemented a vigorous water change regimen, which by itself, was fruitless due to the fact, the phosphates would show reduced for about 24 hours, then higher than before the water change within 2 days. I knew what was happening. The water changes were causing more to be released from the rocks and more released than what had been there before..

I then added to this by upping my lighting period on my turf scrubber, larger and more frequent water changes (130 gallons every 3 weeks on a 340 gallon system) and then starting low doses of lanthinum. just a couple ml a day in 10 micron filter sock with tank water. Then slowly upped that to a max of 20 ml a day within 2 months.

I dropped my phosphates from as high as .66 ppm down to .04 ppm in a 3 month timeframe.

At the end I stopped the Lanthinum dosing and let my current filtration try to handle everything. And it would go from .04 to .1 within 4-5 days . I went on a ten day vacation this summer and lost an alveopora because my phosphates were under control at .04 when I left and .19 when I got back. So, I started vodka dosing on top of everything else, and finally have phosphates routinely around .06 to .08 ppm now no matter what day of the week I test. My turf scrubber has a softball or larger sized ball of hair algae within 3-4 days tops.

I'm dosing around 7 ml of vodka per day. (Higher than I'd like) which I think is fueling some Cyano outbreaks, but, it's also keeping my phosphates under .1 without any water changes and without dosing lanthinum chloride.

My corals are showing signs of growth and happiness with the consistent phosphates. Alkalinity is staying consistent between 8.0 and 8.5. So, I think I'm in the sweet spot and have finally got most of the phosphates detached from the rocks.

It's a battle, but, I am so thankful I started my tank with an algae turf scrubber. I have not had issues with hair algae in the display even with the .66 ppm phosphates. The only side effect was corals just losing their flesh for no apparent reason. Many SPS do not like high phosphates and I found out will lose their flesh in high phosphate water.

My tank is 4 years old and the rocks have been stored dried from a previous tank they were in 7 years ago. I never washed the rocks, just threw them in this tank and started the cycle over. So, they probably added to the problem rather than being part of the solution...

Just my experience with bound phosphates!

 

[LRT]

I had issues with my corals dying fairly rapidly. Couldn't figure out why, so I sent my water off for an ICP test. The only issue was my phosphates were detected at .56 ppm.

I implemented a vigorous water change regimen, which by itself, was fruitless due to the fact, the phosphates would show reduced for about 24 hours, then higher than before the water change within 2 days. I knew what was happening. The water changes were causing more to be released from the rocks and more released than what had been there before..

I then added to this by upping my lighting period on my turf scrubber, larger and more frequent water changes (130 gallons every 3 weeks on a 340 gallon system) and then starting low doses of lanthinum. just a couple ml a day in 10 micron filter sock with tank water. Then slowly upped that to a max of 20 ml a day within 2 months.

I dropped my phosphates from as high as .66 ppm down to .04 ppm in a 3 month timeframe.

At the end I stopped the Lanthinum dosing and let my current filtration try to handle everything. And it would go from .04 to .1 within 4-5 days . I went on a ten day vacation this summer and lost an alveopora because my phosphates were under control at .04 when I left and .19 when I got back. So, I started vodka dosing on top of everything else, and finally have phosphates routinely around .06 to .08 ppm now no matter what day of the week I test. My turf scrubber has a softball or larger sized ball of hair algae within 3-4 days tops.

I'm dosing around 7 ml of vodka per day. (Higher than I'd like) which I think is fueling some Cyano outbreaks, but, it's also keeping my phosphates under .1 without any water changes and without dosing lanthinum chloride.

My corals are showing signs of growth and happiness with the consistent phosphates. Alkalinity is staying consistent between 8.0 and 8.5. So, I think I'm in the sweet spot and have finally got most of the phosphates detached from the rocks.

It's a battle, but, I am so thankful I started my tank with an algae turf scrubber. I have not had issues with hair algae in the display even with the .66 ppm phosphates. The only side effect was corals just losing their flesh for no apparent reason. Many SPS do not like high phosphates and I found out will lose their flesh in high phosphate water.

My tank is 4 years old and the rocks have been stored dried from a previous tank they were in 7 years ago. I never washed the rocks, just threw them in this tank and started the cycle over. So, they probably added to the problem rather than being part of the solution...

Just my experience with bound phosphates!

What species of corals showed signs of tissue loss with those levels of Phosphates? Rich Ross has a tank with what looked like almost every species of coral in it with even higher levels than yours that looked to be thriving. I know I've seen a cpl acro dominant reefs here with higher levels of Phosphates than that so I wonder if your issue wasn't elevated phosphates and something else. Or maybe even it was your issue because you didn't have correct balance of bioload in your substrate and on your rock surfaces. I could be totally wrong in my thinking on that. Its crazy how some of these reefs can function and absouloutely thrive with outrageous numbers and some have the issues you point out.

 

[Treefer32]

My Acros were fine. My large 10-12" stunner chalice started losing flesh. It was ugly. Flesh just stripped off it all over. When I lowered the phosphates down under .2 ppm, the flesh stopped stripping off and it grew new skeleton over the old dead tissues and grew new tissues. Now it's bigger and nicer than it was. . . I lost some stylaphora and a birdsnest in high phosphates as well. A huge colony probably around 12-14" of stylaphora cascade died in the higher phosphates. The polyps just all fell off within a 3 day period. I had to cut the dead skeleton out of my rock with a bone cutter.

Other Stylaphora were fine, just this species of it died, it was a gold / yellow stylaphora. I have two colonies of purple stylaphora that were fine.

 

[Treefer32]

I should add I have several colonies of acropora doing great, colorful and growing, spreading out, Orange Kryptonite that's encrusting all over.

I would say my acans suffered the most in high phosphates. after 3 years they're finally growing new heads and puffing up to be like normal acans. They were always deflated and have never done well for me.

I have xenia, a massive toadstool,a massive GSP rock, and orange ricordea that loved the phosphates.

 

[LRT]

I should add I have several colonies of acropora doing great, colorful and growing, spreading out, Orange Kryptonite that's encrusting all over.

I would say my acans suffered the most in high phosphates. after 3 years they're finally growing new heads and puffing up to be like normal acans. They were always deflated and have never done well for me.

I have xenia, a massive toadstool,a massive GSP rock, and orange ricordea that loved the phosphates.

I'm sorry to hear that!
I wonder if certain species have developed defense mechanisms to cope with higher levels of Phosphates?
If certain pathogens are able to thrive in a younger less mature reef with higher levels of Phosphates as opposed to an older reef with same levels?
I can tell you ive had tissue necrosis in my system and it only affected one specific shroom and nothing else and I had many species of shrooms housed with it at the time.

 

[Randy Holmes-Farley Verified Community Expert]

I'm not sure why the discrepancy, but some reefs thrive really well even at >1 ppm phosphate:

Skeptical Reefkeeping 9: Test Kits, Chasing Numbers and Phosphate

By Rich Ross and Chris Jury There are many standard parameters in the reefkeeping world that aquarists strive to match in their home reefs – water quality,

reefs.com

Rich’s 150 gallon display, on a 300 gallon system, is running a phosphate level of 1.24 ppm, a level at 24.8 times higher than the often recommended .05 ppm. Photo by Richard Ross.

 

[LRT]

I'm not sure why the discrepancy, but some reefs thrive really well even at >1 ppm phosphate:

Skeptical Reefkeeping 9: Test Kits, Chasing Numbers and Phosphate

By Rich Ross and Chris Jury There are many standard parameters in the reefkeeping world that aquarists strive to match in their home reefs – water quality,

reefs.com

Rich’s 150 gallon display, on a 300 gallon system, is running a phosphate level of 1.24 ppm, a level at 24.8 times higher than the often recommended .05 ppm. Photo by Richard Ross.

I think this is the tank I was thinking about. I could of sworn @Thales mentioned in his thread here that a different system was running even higher Phosphates and they where experimenting with lanthanum in the skimmer with success on it.
How and why is it thriving on such high levels of phosphates is mind boggling.
Makes me think of recent upgrade and how my PH wouldn't stabilize until I was able to dose Nitrate and Phosphate levels back to the level they where previously at before the upgrade.
Wonder what would happen if levels where lowered in this system and if after time the bioload thats established needs certain higher levels to function properly to maintain that balance!

 

[Treefer32]

I think this is the tank I was thinking about. I could of sworn @Thales mentioned in his thread here that a different system was running even higher Phosphates and they where experimenting with lanthanum in the skimmer with success on it.
How and why is it thriving on such high levels of phosphates is mind boggling.
Makes me think of recent upgrade and how my PH wouldn't stabilize until I was able to dose Nitrate and Phosphate levels back to the level they where previously at before the upgrade.
Wonder what would happen if levels where lowered in this system and if after time the bioload thats established needs certain higher levels to function properly to maintain that balance!

I think this is the tank I was thinking about. I could of sworn @Thales mentioned in his thread here that a different system was running even higher Phosphates and they where experimenting with lanthanum in the skimmer with success on it.
How and why is it thriving on such high levels of phosphates is mind boggling.

I'm not sure why the discrepancy, but some reefs thrive really well even at >1 ppm phosphate:

Skeptical Reefkeeping 9: Test Kits, Chasing Numbers and Phosphate

By Rich Ross and Chris Jury There are many standard parameters in the reefkeeping world that aquarists strive to match in their home reefs – water quality,

reefs.com

Rich’s 150 gallon display, on a 300 gallon system, is running a phosphate level of 1.24 ppm, a level at 24.8 times higher than the often recommended .05 ppm. Photo by Richard Ross.

Wow! that's awesome! And according to the Redfield Ration 16:1 NItrates to phosphates is what was discovered to be fairly constant in the ocean. Now does that ratio hold true in large mixed reefs in the ocean? I don't know, but, that is interesting. I'm wondering if there's different bacteria that thrive with phosphates that high, that we don't have in many of our reef systems? It's possible the wrong bacteria take over? Or coral diseases thrive in closed systems at higher levels that wouldn't normally do well in the ocean? There's so many variables in a closed system where new types of bacteria can't form unless they're introduced. If there's anything I've learned about the hobby now, it's about what gets people to buy more stuff... So, if we only dose stuff that thrives in <.1 phosphates, then we'll never know if there'd be a way to keep things in balance at above 1ppm. I only monitor phosphates I don't monitor nitrates. It's possible when my phosphates got up to .66 ppm that my nitrates were not in balance, instead of 16:1 maybe they were 50 to 1 or 2 to 1. . . I don't know. All I know is that I wouldn't be growing as much hair algae in my turf scrubber if I didn't have nitrates. and with 26 fish, I'm certain I have them.

Makes me think of recent upgrade and how my PH wouldn't stabilize until I was able to dose Nitrate and Phosphate levels back to the level they where previously at before the upgrade.
Wonder what would happen if levels where lowered in this system and if after time the bioload thats established needs certain higher levels to function properly to maintain that balance!