Aragonite sand/rock phosphate binding

[fushi]

@Randy Holmes-Farley I am trying to figure out a solution to aragonite dry rock and dry sand binding phosphate in a new aquarium.
Is it a biological process or could I just stick all the sand in a bucket of saltwater and some trisodium phosphate for a few weeks, rinse it off then add it to the aquarium and expect it to not bind anymore phosphate.

Everytime I use caribsea dry aragonite sand and rock it seem I have to dose phosphate for a year before it stays detectable.
Currently I’m dosing 0.34ppm a day trisodium phosphate.

I dose 0.01ppm TSP solution every hour and add another 0.1ppm at night; when I test in the morning I get between 0.01 and 0.

 

[tbrown]

When I make new Aragocrete rocks I dump some phosphates into the final soak water. It does seem to help.

ETA: I'm dosing trisodium phosphate.

 

[ScottB]

When I make new Aragocrete rocks I dump some phosphates into the final soak water. It does seem to help.

ETA: I'm dosing trisodium phosphate.

Smart.

I've made the mistake of adding dead, clean rock to a sump or display and PRESTO! No more PO4 detected. Oof.

 

[Dan_P]

Smart.

I've made the mistake of adding dead, clean rock to a sump or display and PRESTO! No more PO4 detected. Oof.

@Garf, your secret is discovered.

 

[Garf]

@Garf, your secret is discovered.

Lol, I must feed a lot compared to some others.

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley I am trying to figure out a solution to aragonite dry rock and dry sand binding phosphate in a new aquarium.
Is it a biological process or could I just stick all the sand in a bucket of saltwater and some trisodium phosphate for a few weeks, rinse it off then add it to the aquarium and expect it to not bind anymore phosphate.

Everytime I use caribsea dry aragonite sand and rock it seem I have to dose phosphate for a year before it stays detectable.
Currently I’m dosing 0.34ppm a day trisodium phosphate.

I dose 0.01ppm TSP solution every hour and add another 0.1ppm at night; when I test in the morning I get between 0.01 and 0.

If you equilibrate the rock at 0.1 ppm phosphate remaining in solution before putting the rock in the tank, it won’t take up more later unless the level is higher than 0.1 ppm.

 

[fushi]

If you equilibrate the rock at 0.1 ppm phosphate remaining in solution before putting the rock in the tank, it won’t take up more later unless the level is higher than 0.1 ppm.

Is there a by way to estimate how much PO4 aragonite can bind? Like say I have 10 lbs of sand and I add x amount TSP to the soaking water it will equilibrate at 0.1 ppm?

 

[Randy Holmes-Farley Verified Community Expert]

Is there a by way to estimate how much PO4 aragonite can bind? Like say I have 10 lbs of sand and I add x amount TSP to the soaking water it will equilibrate at 0.1 ppm?

Not without testing. it depends entirely on the exposed surface area (which few if any reefers know), as well as pH and the phosphate concentration.

 

[fushi]

Not without testing. it depends entirely on the exposed surface area (which few if any reefers know), as well as pH and the phosphate concentration.

I think I may experiment with some sand since its grain size is generaly known. As for the PH does higher PH mean more phosphate binding or the reverse?

 

[Randy Holmes-Farley Verified Community Expert]

I think I may experiment with some sand since its grain size is generaly known. As for the PH does higher PH mean more phosphate binding or the reverse?

Size may be somewhat known, but surface area of a rough particle assembly is much more complicated. It might be mostly dominated by the small end, including dust.