Should I be dosing phosphate and how long for dry rock to absorb phosphate?

thatone08

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Phosphate has been consistently reading at 0 with Hanna ULR phosphate checker.

Quick background on tank. 1year 4 month old 30 long with sump for total of 40 gallons. Have experienced diatoms, Dino’s or Chrysophytes(sp?) unsure which because did not Id under microscope, followed by Cyano. Manually removed all that and started testing daily, noticing 0 readings for phosphates.

Unsure if this is due to the rock absorbing it, or growth on the rock. Rock looks to appear to have diatoms, green film algae, some beginnings of coraline, some small spots of cyano, and a tiny bit of hair algae that was removed by hermits, and some small tufts of what I believe was turf algae.

Out of fear of another large cyano/dino/etc outbreak I started dosing neophos to atleast ensure it isn’t to low, and to ensure my torches and Colorado sunburst have access to some phosphate. Only negative I have noticed is film algae accumulating faster on the glass. Positive I noticed nitrates don’t climb as fast as when I’m not dosing.

How long does it take rock to absorb phosphate before it will start testing higher in the water column?

Is it that the rock hasn’t absorbed enough phosphate or is the growth on the rock consuming it? Should I stop dosing phosphate?

IMG_8699.jpeg IMG_8698.jpeg IMG_8697.jpeg IMG_8696.jpeg IMG_8695.jpeg
 

rishma

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Here are my thoughts. Basically I agree with @KrisReef

I see some growth on your rock, but it’s not that significant so my guess is it not a huge consumer of phosphate.

Your calcium carbonate surfaces will bind a lot of phosphate. While I may not have the mechanism exactly right (Randy will straighten it out) my observation is new rock will bind a lot of phosphate until it reaches some equilibrium with the water. After that point the concentration stops dropping to zero with addition of phosphate sources to water unless you are doing something else to remove it.

How long that takes will depend on many things including the surface area, the amount of phosphate added, and certainly many things I have not thought of. I don’t think the time is knowable.

My advice, if it’s dropping to zero keep dosing and keep testing. Increasing the dose will speed up the process though I don’t know what a max safe dose is. I’d ask @Randy Holmes-Farley

I also really recommend making a diy phosphate when you are done with your neophos. You’ll know the concentration and the purity and it’s way cheaper.
 
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thatone08

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Here are my thoughts. Basically I agree with @KrisReef

I see some growth on your rock, but it’s not that significant so my guess is it not a huge consumer of phosphate.

Your calcium carbonate surfaces will bind a lot of phosphate. While I may not have the mechanism exactly right (Randy will straighten it out) my observation is new rock will bind a lot of phosphate until it reaches some equilibrium with the water. After that point the concentration stops dropping to zero with addition of phosphate sources to water unless you are doing something else to remove it.

How long that takes will depend on many things including the surface area, the amount of phosphate added, and certainly many things I have not thought of. I don’t think the time is knowable.

My advice, if it’s dropping to zero keep dosing and keep testing. Increasing the dose will speed up the process though I don’t know what a max safe dose is. I’d ask @Randy Holmes-Farley

I also really recommend making a diy phosphate when you are done with your neophos. You’ll know the concentration and the purity and it’s way cheaper.
is there a post on how to make the DIY?
 

rishma

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is there a post on how to make the DIY?
At the top of the forum there is a sticky for DIY chemistry. The tread below is linked in there. There might be others too.

I ordered some sodium phosphate online and mixed up a solution so that 1ml would add 0.03 ppm to my tank. I did it that way for convenient dosing.


Phosphate Dosing
www.reef2reef.com

Starting Trisodium Phophate and Calcium Nitrate dosing, need help with recipe

As my tank is growing I'm fighting with very low phosphate and nitrate. I have been feeding more and adding reef roids and AB+ but still have very low numbers. Just received my Na3PO4 and Ca(NO3)2 from Loudwolf. I have looked for a calculator/recipe but can't find one for these reagents. Any...
www.reef2reef.com
www.reef2reef.com
 

Dorsetsteve

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I feel like I have a lot of follow up questions to this one and it gives me the squinties…

So this tank is over a year old?
Has healthy live stock? Many fish?
Has a problem algae/bacteria?
Consumers phosphate disproportionately to Nitrate, what is the nitrate?
 

Randy Holmes-Farley

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Phosphate has been consistently reading at 0 with Hanna ULR phosphate checker.

Quick background on tank. 1year 4 month old 30 long with sump for total of 40 gallons. Have experienced diatoms, Dino’s or Chrysophytes(sp?) unsure which because did not Id under microscope, followed by Cyano. Manually removed all that and started testing daily, noticing 0 readings for phosphates.

Unsure if this is due to the rock absorbing it, or growth on the rock. Rock looks to appear to have diatoms, green film algae, some beginnings of coraline, some small spots of cyano, and a tiny bit of hair algae that was removed by hermits, and some small tufts of what I believe was turf algae.

Out of fear of another large cyano/dino/etc outbreak I started dosing neophos to atleast ensure it isn’t to low, and to ensure my torches and Colorado sunburst have access to some phosphate. Only negative I have noticed is film algae accumulating faster on the glass. Positive I noticed nitrates don’t climb as fast as when I’m not dosing.

How long does it take rock to absorb phosphate before it will start testing higher in the water column?

Is it that the rock hasn’t absorbed enough phosphate or is the growth on the rock consuming it? Should I stop dosing phosphate?

IMG_8699.jpeg IMG_8698.jpeg IMG_8697.jpeg IMG_8696.jpeg IMG_8695.jpeg

I agree with the above posts and I'd probably continue dosing while getting herbivores to consume any pest algae. Note that white rock is not the norm or the goal.

You probably already know this, but this is what a rock from the ocean looks like. This is from TBS, a rock aquaculture business.. It is not white, it is more of a tan color overall, presumably from things growing on the rock.



1734790019300.png
 
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thatone08

thatone08

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At the top of the forum there is a sticky for DIY chemistry. The tread below is linked in there. There might be others too.

I ordered some sodium phosphate online and mixed up a solution so that 1ml would add 0.03 ppm to my tank. I did it that way for convenient dosing.


Phosphate Dosing
www.reef2reef.com

Starting Trisodium Phophate and Calcium Nitrate dosing, need help with recipe

As my tank is growing I'm fighting with very low phosphate and nitrate. I have been feeding more and adding reef roids and AB+ but still have very low numbers. Just received my Na3PO4 and Ca(NO3)2 from Loudwolf. I have looked for a calculator/recipe but can't find one for these reagents. Any...
www.reef2reef.com
www.reef2reef.com
Thank you!
 
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thatone08

thatone08

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I feel like I have a lot of follow up questions to this one and it gives me the squinties…

So this tank is over a year old?
Has healthy live stock? Many fish?
Has a problem algae/bacteria?
Consumers phosphate disproportionately to Nitrate, what is the nitrate?
lol the squinties, I’m going to use that!

Yes over a year old.

Healthy live stock, 2 Picasso clowns, 1 purple fire fish, 1 long nose hawk fish. All eat like pigs. Healthy snails and hermits that are very active. 1 month since I have added 2 new low end torches and the nem. All seem to be doing very well.

Not really a problem, had some issue with bacteria bloom when cycling, added first corals that struggled, believe it had to do with the low phosphate, loss of color almost bleaching, at par levels around 100-150.

Then came the Dino’s/chrysophates that ultimately took them out. So I stopped doing regular water changes, and started to feed more to make it less hospitable for it.

Then cyano came, not a believer in using antibiotics unless it’s something really important, so I manually removed and started testing daily, and dosing phosphate. This so far has kept the cyano from coming back. Full force.

Currently what I am seeing is what is in the picture, not super concerned as it’s not producing snotty bubbles, or large tufts of filamentous algae, some purple spots that I believe to be remnant of cyano but don’t blow off as easily, but can be brushed off easily.

Nitrate currently is 12, it was hitting 20-25 before dosing phosphate. Now it stays pretty much under 15 before I do a water change.

Ultimately unsure if the growth on the rock is able to consume phosphate that quickly, or my rock and bio media are just soaking it up still.

Sorry if this made your eyes even more squinty.
 
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thatone08

thatone08

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I agree with the above posts and I'd probably continue dosing while getting herbivores to consume any pest algae. Note that white rock is not the norm or the goal.

You probably already know this, but this is what a rock from the ocean looks like. This is from TBS, a rock aquaculture business.. It is not white, it is more of a tan color overall, presumably from things growing on the rock.



1734790019300.png
Thanks Randy.

I do understand that it’s not supposed to be white, and that with the issue I had so far with dry Marco rock that I was going to have some uglies. Just was unsure if the rock just hasn’t reached equilibrium to the water, or the growth is something more than just typical maturing of the rock. That is uptaking the phosphate as quickly as i can put it in.

I haven’t noticed any I should stop negatives yet from dosing, so I will continue to dose until I see it consistently around .04-.03.
 

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