Rock absorbing nutrients?

[Dan_P]

Okay, I think I understand, but maybe we had different goals.

Let's say you have a running tank without substrate and a known PO4 level. And you wanted to fill that tank with x kilograms of your substrate. Would you be able to predict the PO4 adsorption/binding based on that? Or, could you create a phosphate solution to soak the substrate in, so it would have a minimal effect on the PO4 levels of the tank?

That was my initial goal, but it turned out to be difficult to approximate especially when testing in very small Jars.
In the end, I didn't go the fancy "math/chemistry" way and instead opted for the "engineering" way by simply adding substrate in batches and countering the measured delta in phosphate levels each day by dosing It gets the job done, but is less elegant

I still dropped to undetectable levels a few times (and still occasionally do when adding more)... Some dinos appeared but dosing nutrients and getting all trace elements back into order according to an ICP-MS test fixed the issue quite fast... Oddly enough Strontium appeared to make the difference for the dinos in the end, but I think that was pure coincidence

Have you published any of those studies here on R2R yet? Would be an interesting read

Have not published details yet. Experiment still in progresss.

The small jar approach could have worked or you could have performed the batch treatment with PO4 outside the aquarium before adding it. That would have been done at a larger scale and with ample to test. Stirring the water would have required a small powerhead.

The appearance of dinoflagellates on newly added sand would not be surprising. Dinoflagellate growth on old surfaces after adding new sand would be interesting.

 

[Dan_P]

I think an iterative dose and measure approach would work best. It takes a lot, but one could also substantially overshoot and then be stuck over target.


It can keep on absorbing more and more if the amount in the water is sufficient. Then it could release that later when you try to keep it lower.

Agree ^^^ The maximum concentration can be at or slightly above the target.

A large volume of water to rock volume will ease the pain of frequently dosing phosphate. Observing whether there is progress in saturating the aragonite surface, sand or rock, can be done by measuring the phosphate concentration several times the first day to obtain a baseline adsorption rate. After a two or three phosphate doses, measure the rate again. You don’t need many points. Every six hours can be informative.

 

[EnterName]

Have not published details yet. Experiment still in progresss.

I will be patiently waiting

The small jar approach could have worked or you could have performed the batch treatment with PO4 outside the aquarium before adding it. That would have been done at a larger scale and with ample to test. Stirring the water would have required a small powerhead.

Yes, I just got tired of having buckets full of sand sitting around with nowhere to put them, so I decided to just go for it and hoped small batches wouldn't make a difference in a 171gal tank. Apparently I was wrong, but then again: I run my tank below 0.05ppm PO₄ so the buffer will be limited.

The appearance of dinoflagellates on newly added sand would not be surprising. Dinoflagellate growth on old surfaces after adding new sand would be interesting.

Interestingly the dinos (Ostreopsis spp.) appeared on the little bit of old sand from the previous system that I transferred to keep a little bit of the microfauna (not more than 250mL of sand). And obviously the glass of the new tank was covered as well. The rocks were only slightly affected (that was the point where I actually got nervous).

The dinos pretty much fully disappeared after bringing nutrients and trace elements back to normal. I only see a few Amphidinium spp. cells in some weird inactive state on the backwall (Second image, page 1, post #3 on my thread, they are basically circular instead of oval). The only active cells I see are present on some coral tissue that got hurt during the transfer.

It's really weird how my tank went from Prorocentrum spp., through Ostreopsis spp., to Amphidinium spp. over the years while never really struggling with actual outbreaks, and always side by side with a decent amount of diatoms because my silicate levels were always elevated.

 

[Dan_P]

I will be patiently waiting


Yes, I just got tired of having buckets full of sand sitting around with nowhere to put them, so I decided to just go for it and hoped small batches wouldn't make a difference in a 171gal tank. Apparently I was wrong, but then again: I run my tank below 0.05ppm PO₄ so the buffer will be limited.


Interestingly the dinos (Ostreopsis spp.) appeared on the little bit of old sand from the previous system that I transferred to keep a little bit of the microfauna (not more than 250mL of sand). And obviously the glass of the new tank was covered as well. The rocks were only slightly affected (that was the point where I actually got nervous).

The dinos pretty much fully disappeared after bringing nutrients and trace elements back to normal. I only see a few Amphidinium spp. cells in some weird inactive state on the backwall (Second image, page 1, post #3 on my thread, they are basically circular instead of oval). The only active cells I see are present on some coral tissue that got hurt during the transfer.

It's really weird how my tank went from Prorocentrum spp., through Ostreopsis spp., to Amphidinium spp. over the years while never really struggling with actual outbreaks, and always side by side with a decent amount of diatoms because my silicate levels were always elevated.

In my experimental aquaria and in past experiments, i have somehow managed to create pelagic Amphidinium blooms. EDIT: you could have a large pelagic dinoflagellate population and not notice it.

Your mention of inactive Amphidinium cells leads me to ask what causes the rapidly, flitting about Amphidinium cell to settle on a surface? I wasn’t going to call them inactive only because I think that I can see flagella movement. Also, I have seen the chubby round version though I don’t recall seeing a vacuole (?) in the dead center of the cell.

 

[EnterName]

I will be patiently waiting


Yes, I just got tired of having buckets full of sand sitting around with nowhere to put them, so I decided to just go for it and hoped small batches wouldn't make a difference in a 171gal tank. Apparently I was wrong, but then again: I run my tank below 0.05ppm PO₄ so the buffer will be limited.


Interestingly the dinos (Ostreopsis spp.) appeared on the little bit of old sand from the previous system that I transferred to keep a little bit of the microfauna (not more than 250mL of sand). And obviously the glass of the new tank was covered as well. The rocks were only slightly affected (that was the point where I actually got nervous).

The dinos pretty much fully disappeared after bringing nutrients and trace elements back to normal. I only see a few Amphidinium spp. cells in some weird inactive state on the backwall (Second image, page 1, post #3 on my thread, they are basically circular instead of oval). The only active cells I see are present on some coral tissue that got hurt during the transfer.

It's really weird how my tank went from Prorocentrum spp., through Ostreopsis spp., to Amphidinium spp. over the years while never really struggling with actual outbreaks, and always side by side with a decent amount of diatoms because my silicate levels were always elevated.

In my experimental aquaria and in past experiments, i have somehow managed to create pelagic Amphidinium blooms. EDIT: you could have a large pelagic dinoflagellate population and not notice it.

Your mention of inactive Amphidinium cells leads me to ask what causes the rapidly, flitting about Amphidinium cell to settle on a surface? I wasn’t going to call them inactive only because I think that I can see flagella movement. Also, I have seen the chubby round version though I don’t recall seeing a vacuole (?) in the dead center of the cell.

I frequently take samples with a plankton net 11μm, so I would have expected to notice pelagic cells, but it might still be possible.

I referred to the chubby circular ones as inactive where I never saw flagella or any movement at all. The "normal" cells are actively swimming and seem to use their flagella all the time. I have not looked into resting cysts of Amphidinium (if they have any) maybe that's when the central pyrenoid becomes so prominent just like we see in benthic Prorocentrum species like P. lima. But it's certainly interesting to have them settle into algae and biofilm on the back wall rather than substrate. It might indeed be not a typical benthic species. I'm currently gathered taxonomic data and keys of all sorts. I will look into Amphidinium but for most dinoflagellates you need electron microscopy to distinguish species.

 

[keagan]

It would be interesting to test saturation methods in identical buckets with the same amount of dry rock, salinity, source water, etc. Test slow dosing phosphate and ammonium chloride v a large amount infrequently v a biological source like a 20g cocktail shrimp. Do we reach equilibrium faster using any of the above?

 

[Randy Holmes-Farley Verified Community Expert]

It would be interesting to test saturation methods in identical buckets with the same amount of dry rock, salinity, source water, etc. Test slow dosing phosphate and ammonium chloride v a large amount infrequently v a biological source like a 20g cocktail shrimp. Do we reach equilibrium faster using any of the above?

What sort of equilibrium ae you referring to? You mean the phosphate/rock equilibrium?

Phosphate binding to calcium carbonate rock is controlled by the rock surface area, and unless organics or bacteria are blocking some of the surface area, the amount that binds is only a function of the equilibrium phosphate concentration in the water (higher means more binding). .

 

[keagan]

What sort of equilibrium ae you referring to? You mean the phosphate/rock equilibrium?

Phosphate binding to calcium carbonate rock is controlled by the rock surface area, and unless organics or bacteria are blocking some of the surface area, the amount that binds is only a function of the equilibrium phosphate concentration in the water (higher means more binding). .

Sorry that wasn't clear. Chemistry isn't my stronge suit, that is what I mean.

This is the way this layman was looking at it:
A phosphate dose → PO₄ spikes → rock adsorbs it → water returns toward 0ppm.
Another phosphate dose → same thing happens.

A decomposing shrimp → continuously generates PO₄ → rock keeps seeing phosphate.

Or the shrimp speeds biofilm development on the rock and blocks access points.

I don't really have a hypothesis I just think it would be interesting to observe if release pattern or source matters. From what you said though I'm assuming this is already well understood for those with a better grasp of the science .

 

[Randy Holmes-Farley Verified Community Expert]

OK, thanks for the clarification.

You volunteering to run an experiment? :)

Yes, phosphate absorption onto and into aragonite is well studied by both reefers and chemical oceanographers. It's an important process in coastal waters.

Here's a study Jonas Roman did:

@JonasRoman


https://www.reef2reef.com/threads/how-much-phosphate-can-a-phosphate-free-limestone-absorb.1140207/

and here's a typical oceanographer study:

https://www.aoml.noaa.gov/flbay/millero1.html

 

[keagan]

OK, thanks for the clarification.

You volunteering to run an experiment? :)

Yes, phosphate absorption onto and into aragonite is well studied by both reefers and chemical oceanographers. It's an important process in coastal waters.

Here's a study Jonas Roman did:

@JonasRoman


https://www.reef2reef.com/threads/how-much-phosphate-can-a-phosphate-free-limestone-absorb.1140207/

and here's a typical oceanographer study:

https://www.aoml.noaa.gov/flbay/millero1.html

If it's worth doing what I outlined above I've already been buying up dry rock for a new system so it would be really cheap to do. I would happily run the proposed experiment. However you have me wondering if anything of note could be observed, with a large body of literature already existing on the subject. Be blunt with me, I'm not going to be offended is it a waste of time? Also thanks for sharing your expertise :).

 

[Randy Holmes-Farley Verified Community Expert]

If it's worth doing what I outlined above I've already been buying up dry rock for a new system so it would be really cheap to do. I would happily run the proposed experiment. However you have me wondering if anything of note could be observed, with a large body of literature already existing on the subject. Be blunt with me, I'm not going to be offended is it a waste of time? Also thanks for sharing your expertise :).

What could be shown was if (and how much) the presence of bacteria on the rock impact phosphate absorption to rock. I would find that interesting, but I don't think it would change anyone's cycling plans.

 

[Dan_P]

I frequently take samples with a plankton net 11μm, so I would have expected to notice pelagic cells, but it might still be possible.

I referred to the chubby circular ones as inactive where I never saw flagella or any movement at all. The "normal" cells are actively swimming and seem to use their flagella all the time. I have not looked into resting cysts of Amphidinium (if they have any) maybe that's when the central pyrenoid becomes so prominent just like we see in benthic Prorocentrum species like P. lima. But it's certainly interesting to have them settle into algae and biofilm on the back wall rather than substrate. It might indeed be not a typical benthic species. I'm currently gathered taxonomic data and keys of all sorts. I will look into Amphidinium but for most dinoflagellates you need electron microscopy to distinguish species.

Good idea using the plankton net. Inhave to wonder if the bacteria blooms reported here are really dinoflagellate blooms. A microscope and plankton net would be all that’s needed to answer my question.

 

[Randy Holmes-Farley Verified Community Expert]

Back when I was having the supposed dino issues in my tank, if I looked at the water in the tank I could see a scintillation in the water that is not there now. I assumed it might be the phyto I was dosing, but I’m still using the same
Phyto at the same dose and do not see it. I now assume I was seeing pelagic dinos.