Backyard Aquaponics
A place to discuss aquaponics

I'm trying to figure out a way to integrate phosphorus into my water along with the fish with out hurting them. if any one has succesfully done this or if anyone knows if the phosphorus would kill or do major harm to my fish i would be really appreciative.

Introducing Phosphorus is likely to lead to major algael bloom problems...

Why are you trying to introduce Phosphorus to your system???

Most fish feeds provide plenty of Phosphorus as well as nitrogen. We usually don't bother testing for the phosphorus though.
I know in Hydroponics there is more talk about the phosphorus levels in relation to the nitrates when it comes time for flowering and fruiting but Aquaponics is different than Hydroponics.

In Aquaponics, most people find they need to perhaps add a little potassium to help get the plants flowering and fruiting. You can do this using a little sea weed extract like sea sol or maxi crop (just make sure it is one of the products with no added nitrogen or fish emulsion.)

There are phosphorus test kits out there for aquarium keeping. Before adding any phosphorus you should probably get the test kit and check and make sure of what your levels are. Chances are you don't need it. And even if you do, I'm not really sure what would be safe (?rock phosphate? maybe but I really don't think you need it.)

Thank you all
I know that the fish don't need it but the flowering plant need the three macro nutrients

My understanding is bone is mostly calcium and phosphorus, That is what we pour all over our salt blocks in the woods to help piney woods deer get better antler development. Fish have bones and need it and the plants and you from the plants...So what I have done is when I cook a deer stew I've been adding the bones to the ap system. It helps buffer the water as well as add those two nutrients. Ground bone meal in low doses will also add iron and nitrates. Be careful on dosage, nitrates will spike. I added to gravel to slow desolution (if thats a word) I also throw crab and crawfish shells in there

That's ingenious i never would have thought of doing that

As noted before, most fish waste has plenty of phosphorus. Do go adding any unless you get a test kit and find the phosphorus totally lacking in your system. We have found that often the lacking macro nutrient that might be limiting the flowering of you plants is potassium and that can easily be added using some maxicrop or seasol.

Not to debate more experienced ap'ers so for now I would say trust their advice but it does go against my understanding of what plants need in the photosynthisis process. Clearly overdosing of nutrients will cause an algae bloom as what happens in the Gulf of Mexico due to ag runnoff but that is mostly nitrates. Phosphates are used in the cellular levels of the plants and is the part that produces the sugars, we remove the plants and I'm sure the fish are getting some from the feed and excrete some but we also remove the fish. There are also much higher levels of phosphorus in seawater than in our ap systems which is where the seaweed gets it. But yes testing is the last word. I use bone which desolves very slowly. I even dosed a little with bone meal when plants were thriving wild. But I only had a little barrel system and rainwater was diluting out my nutes.
A little food for thought.
This link on plants, phosphorus 2nd to nitrates
http://www.ncagr.gov/cyber/kidswrld/plant/nutrient.htm
And this from wikipedia:
http://en.wikipedia.org/wiki/PhosphateEcology of phosphates
"In ecological terms, because of its important role in biological systems, phosphate is a highly sought after resource. Once used, it is often a limiting nutrient in environments, and its availability may govern the rate of growth of organisms. This is generally true of freshwater environments, nitrogen is more often the limiting nutrient in marine (seawater) environments. Addition of high levels of phosphate to environments and to micro-environments in which it is typically rare can have significant ecological consequences. For example, booms in the populations of some organisms at the expense of others, and the collapse of populations deprived of resources such as oxygen (see eutrophication) can occur. In the context of pollution, phosphates are one component of total dissolved solids, a major indicator of water quality."

Yep, Phosphorus deficiency... is rare in AP systems... indeed even in soil systems... and where it does occur is usually related to pH...

Which probably means any deficiency showing in plant growth... is probably more related to other trace element uptake, rather than phosphorus...

As TCL mentioned... Potassium is more important to flowering/fruiting/seeding stages of plant growth... than Phosphorus...

Just what are the parimiters for phosphorus in an ap system??
What are people measuring???
A pond isn't considered poor until over 10PPM and that is also related to the nitrate level.
And Yes, don't add and don't worry about it is not satisfying my curiosity.

Got no idea BRB.... never had a phosphorus problem... or heard of one in an aquaponics system...

If in doubt... add some Seasol/Maxicrop emulsified seaweed extract...

Well I went thru pages and pages on the mineralization of fish waste and all everybody wants to talk about is the mineralization of nitrogen. I finally found a PDF on the breakdown of rainbow trout waste. And it show 2.83% (N) and 2.54% (P) and only 0.1 % potassium (K)
http://www.aps.uoguelph.ca/~aquacentre/ ... Manure.PDF
Which makes me want to question status quo...
While not a problem, wouldn't controlling the level of phosphorus at a level that wouldn't be harmful to the system or the fish but maximize plant growth be a good thing?

That's a 10:10:1 NPK ratio BRB.... which is pretty much a standard NPK fertiliser that you'd buy for soil use...

Sounds just fine to me... and the rest of the article suggests more than adequate trace element provision for the majority of the required elements of plant growth...

A vindication of worm stocked, pellet feed, fish waste media growned aquaponic systems... as far as I can see..

From what I read phosphorus isn't toxic at any level to humans or animals and the only comment made was that at large quantities would clog instestines. So I didn't find any levels or thresholds on how it relates to algae. I guess other factors such as nitrate levels, temperature and sunlight all play a roll and vary any you would vary the threshold. So it's good for plants, including algae..not harmful to fish but algae bloom could produce toxins or lower oxygen levels, clog system up. So if you keep your fish in the dark...
Anyway if anybody comes across the data as it relates to algae blooms please post.

Sorry... that should have read... a 20:20:1 NPK ratio... that is higher than the normal 10:10:1 ratio of most soil fertilisers...