Understanding Phosphates and what they are.

[Boomer]

Types of Phosphorus in a Reef Aquarium and Comments and Observations of Removal by Protein Skimming

Feature Article: Types of Phosphorus in a Reef Aquarium and Comments and Observations of Removal by Protein Skimming — Advanced Aquarist's Online Magazine

 

[DTECH07]

Yes i read that article and was very informative, there site seems to have serveral articals with the looking into. Due to the site i'm looking into the auto refrigerator feeding system but need more research before installing maybe Dec timeline. Thanks

Dtech07

 

[BarrierReef]

Phosphates the good the bad and the ugly. I am a bio-chemist at least I went to college and got a degree in the subject, LOL. As a hobbyist we know that we want phosphates to be low or zero in our tank and are taught that they are bad, and for the most part this is absolutely the fact. Phosphates in high concentrations can be poisonous to our fish, corals and invertebrates. However there is another side to phosphates, the bacteria that grow in our substrate and break down the ammonia, and nitrites need phosphorous to stay healthy and grow, they need phosphates in the tank. Many of the micro cleaners like the pods need the phosphates, some marine biologist, another degree I gathered in my career of education, tells us that some of the invert's that we house like giant clams and even some corals do better with a trace of phosphates in the water. So the next time we look at phosphate in the water we should think, yes I need to drop the the levels to a non-detectable level, however that fact that they are in the water column may not be all that bad.

On of the major arguments for a refugium is that it will remove phosphates naturally, leaving trace amounts in the water column to be utilized by the organisms that need the phosphorous and help out system in other ways. What is sometime seen as bad may have a good side. Of course there is that ugly side when it does get out of control and we get unwanted hair algae growth and it takes over the tank. Thus the good the bad and the ugly side of phosphates.

 

[NanaReefer]

At what levels would you then say are acceptable. Mine usually test at .01-.02.

 

[BarrierReef]

Please note while I do have a degree in marine biology, I have never worked in the field. Generally if the levels are below 0.25 ppm then there is some concern but not a lot of concern. We do want low levels in the tank, at 0.20 ppm's we can get hair algae growth in the primary tank. This is why, I say that phosphates are both good and bad. While we need them to be present in some very low level they need to be at low enough levels so that they do not become toxic to our closed system. On the natural reef, phosphates are kept in check by the constant washing out of naturals sea water, and the number of herbivores that continually consume the algae that grows.

Then we have both organic and inorganic phosphates in our system. This complicates the issues somewhat. Organic phosphate is what we test for and what is utilized by the organisms in the system. The inorganic phosphates settle out and only become viable when there is a pH shift in the water that sufficient to have the ions disassociate.

So this is why, when I talk about phosphates, I call them the good, the bad and the ugly. There is so much to them that works in our tank. So alkalinity plays a role in phosphate uptake, as do the levels of calcium. We tend to look at the nutrient/mineral content in the tank as unilateral but they work together to keep the overall biology of the system in sink. Magnesium plays a significant role as well. I think this is more than we wanted for a simple talk on phosphates. All this to say that while we are told that phosphates are very bad, and for the most part they are something we need to minimize, they do serve a purpose are useful as well.

 

[Boomer]

Organic phosphate is what we test for and what is utilized by the organisms in the system. The inorganic phosphates settle out and only become viable when there is a pH shift in the water that sufficient to have the ions disassociate

No, we do not test for Organic phosphates but a Inorganic phosphates group known as Orthophophates. It is mostly Inorganic phosphates used not Organic. pH sfift has little to do with Organic phosphates it is Inorganic Phosphates. And where do you get phosphates are toxic ? If you read that article I posted you would see some of this.


Generally if the levels are below 0.25 ppm then there is some concern but not a lot of concern

How is that, on coral reefs they on the order of 0.06 ppm and in some places 0.005 ppm.


at 0.20 ppm's we can get hair algae growth

You can get that at any level.


You need to study the subject matter before attempting to answer questions.

 

[BarrierReef]

Boomer, it has been some time, since I studied marine biology and I have to been in a chemistry class for several years as well. I am a bit rusty. Thank you for correcting my error. However the fact is that we do need some minor level in the tank.

 

[BEAU_RN]

Thanks Boomer for all the in-depth yet understandable info on this subject.

 

[Belgian Anthias]

We are 2020.
Recent research on corals and the coral holobiont has shown phosphate does not inhibit calcification and increased phosphate availability does not harm corals. Maybe some of these discussions should be reviewed?
It is known phosphorus availability is one of the main causes of coral bleaching, this if the supply is insufficient to follow increased growth rates ( increased temp, high DOC) supported by high nitrogen availability. High phosphate availability supports the calcification rate and does not slow it down as often published on fora. High nitrate availability slows down the growth of corals! if used as a nitrogen source for growth most organisms using it slow down its growth rate ( +- x5), also algae. ref: Makazi Baharini [nl:makazi:chemie:calcificatie] High phosphate availability does not increase the growth rate of algae, it is the nitrogen source used wich is determent for the growth rate.
If phosphorus becomes the limiting for growth in the coral holobiont, this may harm corals and may provoke symbiodinium secretion. Makazi Baharini [nl:makazi:theorie:koraalverbleking] If nitrogen becomes the limiting factor this will not be the case, not on short notice.
In an established aquarium, the nutrient content cycling in the tank is not known, what we do know is the nutrient reserve not used yet, present in Nitrate and Phosphate.
As it has been shown it is not a good thing if phosphorus becomes the limiting factor for growth, it may be advisable to keep the nutrient reserve at such a level the reserve on its own can not be responsible for phosphorus starvation, this means it is a good thing to keep the nitrate reserve in weight not to exceed 10x the phosphate reserve. For example, if 0.2 ppm phosphate max < 2ppm nitrate.
In the ocean, inorganic nutrients normally are available at very low levels but can unlimited be supplied depending on the exchange rate. In a closed marine aquarium system, it is all about the exchange rate and total availability in the limited environment.
In nature, reef corals meanly make use of organic nutrients, remineralized within the holobiont and the symbiodinium delivering the energy. It seems corals or able to direct there own food supply by managing the DOC availability. ref: Makazi Baharini [nl:makazi:theorie:koraal_holoboint]
As a skimmer removes TOC and DOC constantly, but very limited ( only +- 30%) and very selective, a skimmer plays a very important role in the availability of building materials and the presence of inorganic nutrients, phosphate and nitrate. ref: Makazi Baharini [nl:makazi:het_water:filtratie:eiwitafschuimer]