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Yes there is. Easily available is Seachem Flourish Phosphourous.
There's also Lushgro's KH2PO4.
Contact http://www.singaporehydroponics.com, or there are quite a number of people selling them here (I don't know).
Hi bros,
May I know which fertiliser provide the best source for Phosphorous. Currently I am using LushGro AQA and it does not contain Phosphorous.
Is there a power form of Phosphorous-rich nutrient
tango
Adopt all unwanted neon & cardinal tetra
Yes there is. Easily available is Seachem Flourish Phosphourous.
There's also Lushgro's KH2PO4.
Contact http://www.singaporehydroponics.com, or there are quite a number of people selling them here (I don't know).
KH2PO4 is much cheaper. Just a pinch will do for a week.
Fish food does have Phosphorous.
Precisely ! Why buying PO4 to dose where we can just feed the fish more? Diana Walstad has more details on this in her book "Ecology of the Planted Aquarium". I was revisiting the chapter in the book on plant nutrient from fishfood. Using the data of an average fishfood composition in the book, it works out that a small pinch (~0.4ml) of the Tetra flake food that I use will give about 1+ppm of P in my 100L tank.
So in my next fish-feeding I just add an extra pinch into the water inlet of the surface skimmer : )
Diana Walstad is into non-CO2 method (slow growth) whereas a CO2 enriched tank is completely different (rate of growth and nutrient demand). Do your method and we will see what you get.Originally Posted by dc88
Regards
Peter Gwee
Plant Physiology by Taiz and Zeiger
But isn't P is still P ? After all EI is not to bother about precise level anyway ? High lighting level and CO2 enriched tank would just mean you can dose even more fish food, isn't it ?
In my current tank (2.8 wpg, CO2 enriched), as I do not have any KH2PO4 on hand, so I gradually up the fish food (by measurement of 0.4ml scoop) and can actually see that at some level of fish food adding the plant start pearling.
BTW I still dose trace daily for the micro nutrient, and add K, Mg, Ca weekly at water change because the fishfood and the tap water has low % of these.
My point is that I still need to feed the fish anyway so there is one thing less I need to spend time on (liked buying KH2PO4 and mix them an so for) and my current scheme of dosing Mg, K and Ca I do not worry of overdosing.
Same for NO3, if it is low just feed the fish more. (or drop it into the filter inlet to feed the bacteria).
Then follow by regular water change (goal is to just do 20%every 2 weeks).
The PO4 in the fish food is very little... thus you have to dose alot more. And all that rotting fish food will give you ammonia too. Ammonia triggers algae.
I am not too sure ammonia in moderation is bad - to a well planted tank ammonia actually much preferred by the plants than nitrate.
Allow me to elaborate my thought here, pls feel free to point out any error.
Reference from pg 79 of Diana's book, she models a typical fish food based on common commercial formulation, to be likely have 82000 mg/kg of N and 23000 mg/kg of P.
The Tetra fish food I used is of the density of 20g/100ml (per the lable on the bottle).
If I add 15ml (1 table spoon) into my 100 liter tank OVER A WEEK, which is spread out daily to about 2 feeds per day with 2 small pinch per feed.
The gross addition of N and P into the tank would be N =~ 2.46ppm and P =~0.69ppm .
If I refer to the recommended E.I. target (reference Barr Report site) :
NO3 =5~30ppm (so N =~ 1.1 to 6.7ppm ? )
and PO4 =~1 to 2 ppm (so P =~0.3 to 0.7ppm ?)
Hey, isn't the fishfood route give you about the same ball part of N and P too ?
Fish may accumulate some N and P in their body as flesh and bones (they grow too) but I believe most of it became "fish-shits" into the water : )
I only zoom into the N and P of fish food because the other macro nutrients (Ca, Mg, K,..) and micro trace (Fe, B, ..) are not much in the typical fish food. Hence my PMDD mix focus more on K, Mg and Ca dosage, plus the daily trace drop.
Again my question was to bring up the point for discussion that isn't fish food (if adminstrate in the same discipline as you dose the other PMDD ingrident) can be enough to cover the N and P needs in your planted tank ?
Not at the growth rate with CO2 enrichment.....Do what you think is right and see for yourself. Folks need to learn the hardway sometimes. Note that Diana Walstad's chart states that NH4 is preferred only at levels of 2-0.5ppm, after which NO3 is preferred. Is 2-0.5ppm of NH4 practical in a fish tank? It can only kill your fish if you want that?
Regards
Peter Gwee
Plant Physiology by Taiz and Zeiger
I think that refer to a controlled experiment with a fixed NH4 and NO3 level introduced to the specimen plant and meausre the N remaining over time. But that doesnot mean you have to add 2ppm of NH4 in your tank to begin with !
In a matured planted tank the NH4 will not stay long as NH4, my bet is it get absrob by plants or get convert to NO3 by bacteria pretty fast. Also note that the fishfood is administrated little by little over a week period. So you don't get a large dosage of NH4 but a low sustainable level of NO3 (end product).
If you read the detail in my post, the amount of fish food added is just average, right ? You don't dump that whole table spoon of fish food in one go !
My point is that the gross amount of P and N in our typical daily fish-feeding has about same gross amount of P and N as the recommended PO4 and KNO3 dosing. Do the maths and be surprised !
Last edited by dc88; 3rd May 2006 at 22:29.
Okay, forget what I said. Do what you want...I pretty done with it.
Regards
Peter Gwee
Plant Physiology by Taiz and Zeiger
Looking forward to your results in two weeks time before you change your water... Hope you are right and bring another new school of thought of fertilisation into the community...
I read somewhere that there are differences in organic PO4 (from fish food) and inorganic PO4 (eg. from KH2PO4). Plants preferring the inorganic form. I think it made a differerence when I added KH2PO4 to the tank.
I do feed generously in my tanks. So I don't need to dose NO3 but I still dose 1.5 - 2ppm PO4 weekly.
KH2PO4 is very cheap. That 500g bottle can probably last you a lifetime if you got only small tank to maintain.
koah fong
Juggler's tanks
What if we do the EI recommended dosage WITHOUT changing water?
: )
Anyway, think objectively the missing link in my proposal could be what Juggler points out that there is a difference in plant's uptake of organic P vs inorganic P.
I am not chem expert and looking to the chem-bios expert for guidance. My humble guess is that organic P probably bind with some other compound tightly that it takes efforts to transform to what plants can use. The efforts could be bacteria, chemical reaction in soil, plants root intereaction, etc. I read that most aquatic plant prefer root uptake of P but if abundant of free P in the water may be a different story?
The question is that at the rate of inorganic P dosage of 1-2 ppm why isn't there an exccess P builtup to cause trouble such as algae bloom?
Because of weekly large amount of water change ? Or the tank has so much excess of other stuff that P just never bottoms-up? Anyone ever venture into even higher rate of inorganic P dosage to test the upper limit ? Or because we also up the iron dosage that Fe and P just lock each other up ?
I tried before... For 2 weeks without changing water.. By the end of the 2nd week, GSA started to pop up on the glass and also on some of the leaves... I am not sure why this happens as logically, it shouldn't since everything else remains constant... Maybe my CO2 was flatuating...
But the main reason for changing water is to prevent excessive buildup in the tank which is harmful to the critters... Tom presented the mathematical calculation on the amount of possible buildup...
I know Ranmasatome doses a hellava lot of PO4... Can't remember what is the ppm he does... No algae bloom in his case... But if you CO2 is bad... It will be a problem regardless of how much you dose...
Because logically, when everything is high, but the most important building block is insufficient, any unused will be given to the algae as free food...
Heres is another piece of infor may explain why the inorganic P dosage advantage : (from Wikipedia)
"Monopotassium phosphate (also potassium dihydrogen phosphate, KDP, or monobasic potassium phosphate, MKP) -- KH2PO4 -- is a soluble salt which is used as a fertilizer, a food additive and a fungicide. It is a source of phosphorus and potassium, and is a buffering agent. When used in fertilizer mixtures with urea and ammonium phosphates, it minimizes escape of ammonia by keeping the pH at a relatively low level."
Could it be that the adding of KH2PO4 actually help manage the ammonia to benefit the plant ?
So if you do a combination of generous fish feeding plus adding of KH2PO4 the result could be better than just generous fish feeding ?
Fish food tends to not have enough PO4 relative to NO3/NH4, I add PO4 to the non CO2 tanks as well and NO3.
This helps growth even when the growth is slower due to low CO2.
K+, Ca and Mg, traces etc are also lacking in fish foods.
A simple addition once a week of these in addition to the fish food greatly enahnces the growth and health, not really speeding up the growth, just allowing you to grow more species, more plant density and healthier looking plants.
Regards,
Tom Barr
Yea, but she seems to imply it's support for her method, when in relaity is supports the opposite contention.
That at normal reasonable levels of NH4 and NO3, that the uptake rate of NH4 is near zero, the rate = the slope of the line at less than .2ppm NH4, take a look at that one, now......compare that to the NO3 slope......it's still taking in NO3 at a fairly stable rate right?
That graph supports NO3 uptaske as the preferred source under our normal NH4 conditions.
Well, you do get a fair amount of NH4, you just cannot measure it as it's removed by plants as fast as it's produced.In a matured planted tank the NH4 will not stay long as NH4, my bet is it get absrob by plants or get convert to NO3 by bacteria pretty fast. Also note that the fishfood is administrated little by little over a week period. So you don't get a large dosage of NH4 but a low sustainable level of NO3 (end product).
You are not testing plant tissue are you?
Unlikely, you are testing the water column.
N and P are different than PO4 and NO3.If you read the detail in my post, the amount of fish food added is just average, right ? You don't dump that whole table spoon of fish food in one go !
My point is that the gross amount of P and N in our typical daily fish-feeding has about same gross amount of P and N as the recommended PO4 and KNO3 dosing. Do the maths and be surprised !
Also, what is required to take an organic form of N and P and break it down into a bioavailable plant uptake form? Bacteria, which use what? Lots of O2.
Remember the test kits?
They typically test for total NO3, total NH4 and total PO4.
Not inorganic vs organic forms.
The most biolavailble forms of N and P?
Inorganic, eg: KH2PO4 and KNO3.
You can do the fish food food only method, and reduce the water changes, this works well as long as you don't have too many fish and balance things.
Most have lower light that do this, but adding some KH2PO4, KNO3 will not be the end either.
It'll likely make the tank healthier, now you spoke about cost and $$$.......
Now how much is fish food per unit of N and P vs KH2PO4 and KNO3?
How long do you think 1 kg of KH2PO4 might last? Probably a life time.
Cost here is about 2$, the shipping cost more than the product.
Non CO2 approaches are nice, I fully support them, but they can be improved upon slightly and the plant health can be improved a great deal by simply topping things off with a little KNO3, KH2PO4 once a week.
That does not cause any hassle, and is cheaper than fish food.
For a CO2 enriched tank, this addition is done 2x a week, maybe 3 times if you have higher light.
With a good eye, you extend water changes out longer time frames etc, and the the trade offs might be worth it for you, but if you want good stable consisent on top of your game looking tanks, you have to out in the weekly water changes and do the work, ADA does this, I do this, we know what's up, there's no getting around doing the work in the end, but you might find the trade offs acceptable.
Not everyone demands an ADA level picture perfect tank.
Regards,
Tom Barr
dc88,
The test kit measures total PO4, it does not tell you what is available for the plants or not, same applies to the NO3 test kits.
EI is not really designed for no water changes, you can certainly do it, but it requires a good eye and things just do not do nearly as well over time.
I've done it for several weeks, but I just don't like the look of the tank and health of the plants. Even with lots of testing and maintaining a particular ppm range, it leaves something to be desired when using CO2.
Several very respected judges and aquarist, Amano included agree on this.
You might not need the full 50% water change each week, but 25% etc is a good amount for a min level.
The trade off might be worth it for you though.
That's up to you though.
My focus is more providing an even increasing method to produce helathier plants, no matter what method you chose.
By by passing test kits with EI, this saves folks a lot of trouble and guess work, and the test kits often are inaccurate and do not test for the nutrients/forms of interest.
Adding a few things to the non CO2 method, this enhances the method a great deal.
Adding a little KNO3, or Ca(NO3)2 to a marine planted tank also helps prevent Caulpera melting and produces excellent growth.
EI is just a way to get around test kits. I suppose that is much more my idea along with adding PO4.
PMDD is just the old method + PO4, I just improved upon it, the ideas and foundation was there.
I just added the last piece to the puzzle.
Regards,
Tom Barr
Hi Tom
Is an honor to hear from you directly !
Didn't expect the topic on organic vs inorganic P can generate some much insight and broaden perspective.
Now I can see that from a practical standpoint the "fish food only" route will run into a hard stop for high grow-rate tank. I also discovered a few more points in that chapter of Diana's book that plant may prefer NH4 intake than NO3 but not necessary will grow well with NH4. She said one reason could be NH4 toxicity. So if rely pure fish food to hit the desired high level of NO3 the tank will need to go over the high NH4 peak, and not all type of plants can cope with this even under high light and CO2 level.
Opps, a little off track here. Back to the topic of PO4, thanks for your guidance. This is new frontier to me.
... how much was that PO4 again ? : )
Last edited by dc88; 4th May 2006 at 22:10.
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