Phosphate vs Phosphorus

Fragzilla

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Hello, :)

I'm trying to understand the differnce of the effect of phosphorus vs phosphates on corals, particularly Zoanthids.

I have a filter that claims to oxidise phosphates and turn them into phosphorus.

The reason I want to try to find out the differences between po4 and P and its effects on my zoas is because I could do with getting rid of the gfo and reactors if I'm only removing something that won't do any harm being there in the first place. Obviously there is cause for concern and worry when using GFO and stability is easily lost unless you strip the lot and supplement.

I have tried to learn a bit about phosphates over the years and have been looking more recently also. Is it the ester of phosphoric acid that causes stunted growth or is it the actual element P?

If my zoanthids health and Growth will not be impacted by P' I can make my system really simple and stable.

Can you please help me broaden my understanding on this? Or give an opinion on how element P, Phosphorus reacts with corals and cynidarians (particularly zoas) as opposed to PO4 Phosphates ?

:)
 

pdxmonkeyboy

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My understanding (and although I am new here, I filled pages and pages with notes about marine chemistry) is this.
Aquarium keepers are only concerned with inorganic phosphates.. also called orthophosphates.

While there IS ..or CAN be phosphorous in your aquarium, it is "locked up" or bound to organic matter in some rocks and substrate. This phosphorous can be released into the water column by anaerobic bacteria that use enzymes to "unlock" or liberate orthophosphates.

So, my understanding is that there is NO phosphorous in the water. Maybe in substrate, but not in the water. You couldn't tell anyways as all the common test kits detect the presence of orthophosphates.

If this is correct (And I'm pretty sure it is because gfo, aluminum oxide, and lanthanum chloride all reduce orthophosphate..not phosphorous.) Then I would not ditch your gfo as it is the orthophosphate levels that we test and are known to damage corals.. especially sps.

I don't see how GFO would make your system unstable? Used correctly it should slowly remove orthophosphates in the water column that are being produced through normal biological process in the aquarium.

If you have a low bioload then you could do away with GFO but from my research, gfo only becomes a problem is you start off with way too much, thus stripping all the orthophosphate out of the water... thereby killing everything.

So in short.. My understanding.. phosohorous doesn't react with corals and cynidarians because what is in your water is actually phosphate.. specifically orthophosphate.

And FYI.. I double checked this info in volume 3 of the reef aquarium series before clicking post. I hope this helps.
 

Randy Holmes-Farley

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There is no phosphorus in your reef tank that is not inorganic or organic phosphate.

The claim of that filter is ludicrous if it is exactly what you write. Phosphate is fully oxidized and cannot be oxidized further.

You cannot have and do not want actual phosphorus. It burns in air and water.
 

Cory

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Yeah phosphorous is the element. Phosphate is what is in the water. Its P and O or phosphorus and oxygen (po4). Scientists measure phosphours in its various forms, organically bound phosphorus and inorganically bound phosphorus. This is the way i understand it.

That said, zoas dont need po4 remover. In fact id say more is better for softies, as po4 doesnt effect non calcifying organisms. They use it to build tissues.

But zoas need to eat to grow when po4 is low. This is also true with some calcifying corals. Growth stops when they dont get food like zooplankton. There was a study done to show that phosphate and nitrogen are not enough to grow corals iirc. They grow for a while but stop.
 
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Fragzilla

Fragzilla

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Ok chaps thank you very much for your reply.

When I've had the filter running I get no algae in my tank and the mulm that builds up under my love rock in the sump increases significantly so I was assuming the majority of that was phosphorus.

My Hanna "phosphorus" checker is always reading about 30 ppb.

Is the Hanna checker not actually testing for phosphorus then if it can't actually exist in the water column?
 

Randy Holmes-Farley

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Is the Hanna checker not actually testing for phosphorus then if it can't actually exist in the water column?

It is a stupid marketing distinction from the Hanna phosphate checker to make it look even better.

It detects inorganic phosphate by the same method that most hobby kits use. It just chooses to report the values in units of phosphorus (like changing from feet to inches, or reporting nitrate in ppm nitrate-nitrogen). It should correctly be called ppb phosphate-phosphorus.

Most disturbing, it does not detect organic phosphate (most kits do not; that requires a special digestion step to break down organics), so to report it as if the answer was total phosphorus is wrong.
 

Smarkow

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You cannot have and do not want actual phosphorus. It burns in air and water.

Think this is why Burning River carries such a bite? Jk... kind of... :(
01EA834D-A42E-4D16-BEF5-A5929D968AA8.jpeg
 

Smarkow

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It is a stupid marketing distinction from the Hanna phosphate checker to make it look even better.

It detects inorganic phosphate by the same method that most hobby kits use. It just chooses to report the values in units of phosphorus (like changing from feet to inches, or reporting nitrate in ppm nitrate-nitrogen). It should correctly be called ppb phosphate-phosphorus.

Most disturbing, it does not detect organic phosphate (most kits do not; that requires a special digestion step to break down organics), so to report it as if the answer was total phosphorus is wrong.

Just to be clear, this should still be a/the meter of choice for hobbyists who are monitoring inorganic P and regularly have levels below 0.1? No color subjectivity, premeasured ingredients, and decent reliability, precision?
 

Randy Holmes-Farley

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Just to be clear, this should still be a/the meter of choice for hobbyists who are monitoring inorganic P and regularly have levels below 0.1? No color subjectivity, premeasured ingredients, and decent reliability, precision?

I think the Hanna ultra low is a good choice, yes.
 

debees5

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I think the Hanna ultra low is a good choice, yes.
Randy - my Hanna ultra low (and Hanna ref PO4 checkers) always comes in at .12 to .2 ppm PO4. Any icp test I’ve done show phosphorus reported in ppm (not PPB) and show I’m at .02 ppm phosphorus. These don’t jive at all on conversion. I don’t have much algae, but my lps are never thriving. All my other parameters are usually good. Any advice?

230E80AA-D908-4C0D-AEB6-26E5720F0122.png
 

Randy Holmes-Farley

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Don’t sweat minor differences as you’ll end up pulling your hair out. 0.02 ppm P is about 0.06 ppm phosphate. The uncertainty on both readings puts that not unreasonably far from 0.12 ppm phosphate.
 

becon776

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i bought by phosphate checker long ago. so it is not the ULR one. is there any differemce in reagents? method. or have they just added another decimal place?
 

debees5

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i bought by phosphate checker long ago. so it is not the ULR one. is there any differemce in reagents? method. or have they just added another decimal place?
The reagents for the reg and ulr PO4 checkers have different id/sku Numbers. They both read in ppm. I use both and don’t see a big difference in results..... Hanna makes a calibration fluid to check accuracy, but there is no way to calibrate Hanna checkers.
 

Brad ward

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There is no phosphorus in your reef tank that is not inorganic or organic phosphate.

The claim of that filter is ludicrous if it is exactly what you write. Phosphate is fully oxidized and cannot be oxidized further.

You cannot have and do not want actual phosphorus. It burns in air and water.
Hello randy, I really appreciate all of the chemistry advice you give to this channel to help people.
I do have a question though regarding phosphate and phosphorus.
I just got the results back from ATI labs and they recommend removing any gfo (not using anyway) and to add phosphorus.
My levels are : 0.01 mg/l phosphate
And 2.82 ug/l phosphorus (the u is backwards looking but I don’t have that symbol)
Thanks so much sir
 

Randy Holmes-Farley

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Hello randy, I really appreciate all of the chemistry advice you give to this channel to help people.
I do have a question though regarding phosphate and phosphorus.
I just got the results back from ATI labs and they recommend removing any gfo (not using anyway) and to add phosphorus.
My levels are : 0.01 mg/l phosphate
And 2.82 ug/l phosphorus (the u is backwards looking but I don’t have that symbol)
Thanks so much sir

those values are the same and are measuring the same chemical. The phosphorus atom is only a third of weight of a phosphate ion, so phosphate is 3x as high as phosphorus.
 

Randy Holmes-Farley

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