# dosing problem



## Phantom (25 Sep 2016)

Set up 29.9. 2015


*The tank *
80X35X40 cm, 112 l (optiwhite)

*Cabinet*
80X35X80 cm (ADA style)
*
Lighting*
4AQUA 4X24W T5 (33 cm above tank), Giesemann Aquaflora and Giesemann Midday
*
Filters *
Eheim 2324 thermofilter (Eheim mech, Seachem matrix, Seachem purigen, blue and white pad)

*CO2 *
4 kg set with magnetic solenoid valve, atomizer  

*Substrate*
ADA Tourmaline BC
ADA Bacter 100
ADA Penac W
ADA Penac P
ADA Clear super
ADA Power sand S
ADA Amazonia

*Plants*
Micranthemum "Monte Carlo" 
Microsorum pteropus "Narrow" 
Hydrocotyle tripartita 
Fissidens fontanus-Phoenix moss 
Vesicularia ferriei "Weeping moss" 
Eleocharis acicularis
Bacopa monnieri 'Compact'
*
Ferts* 
Monday (Seachem flourish 2,6 ml, Seachem nitrogen 10 ml, Seachem phosphorus 15 ml, Seachem iron 15 ml)

Tuesday (Seachem trace 7 ml, Seachem iron 15 ml)

Wednesday (Seachem nitrogen 10 ml, Seachem phosphorus 15 ml, Seachem iron 15 ml)

Thursday (Seachem trace 7 ml, Seachem iron 15 ml)

Friday (Seachem flourish 2ml, Seachem nitrogen 10 ml, Seachem phosphorus 15 ml, Seachem iron 15 ml)

Water change: on monday 30 l (osmosis water 21 l, tap water 9 l)


*My question is: at relatively high doses of iron and phosphorus (15 ml daily) tests indicate value of 0 mg/l (JBL, Sera tests). What amount of dosage do you use?*

Blue green algae appeared on the front glass below the substrate, green spot algae on the back glass, Hydrocotyle has yellow spots and green spot algae on the old leaves, Microsorium has brown ends of leaves.


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## kadoxu (26 Sep 2016)

I have a lot of questions... lol

First of all, I believe you shouldn't dose Phosphorus and Iron in the same day... they can react with each other and become unavailable to plants.

Is there a particular reason to use such expensive fertilizers?

What is the temperature of the water?

How long do you run CO2? And what about lighting period?


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## dw1305 (26 Sep 2016)

Hi all, 





Phantom said:


> My question is: at relatively high doses of iron and phosphorus (15 ml daily) tests indicate value of 0 mg/l (JBL, Sera tests). What amount of dosage do you use?


The iron (Fe+++) and phosphorous (PO4---) ions may have reacted together to form insoluble ferric iron phosphate complexes as "kadoxu" suggests, but it maybe the test kit. I'm not very keen on test kits, unfortunately they don't tend to be very reliable, or give repeatable results. 





kadoxu said:


> Is there a particular reason to use such expensive fertilizers?


Nothing at all wrong with the fertilisers, but they are an expensive option. Once a fertilizer (a salt) has gone into solution the ions don't "know" where they came from. If you add potassium nitrate (KNO3) you get K+ and NO3- ions, if you add KCl you get K+ and Cl- ions, and the K+ ions are the same in both cases. 

You can buy complete fertilizers mixes from one of <"our sponsors"> (other sponsors are available). Also have a look at <"The Estimative Index">.

cheers Darrel


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## kadoxu (26 Sep 2016)

dw1305 said:


> Nothing at all wrong with the fertilisers, but they are an expensive option. Once a fertilizer (a salt) has gone into solution the ions don't "know" where they came from. If you add potassium nitrate (KNO3) you get K+ and NO3- ions, if you add KCl you get K+ and Cl- ions, and the K+ ions are the same in both cases.


I only asked because the only reason I got Seachem myself, was because I didn't know about dry salts until someone here told me about them.


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## Phantom (26 Sep 2016)

Hi all,



kadoxu said:


> First of all, I believe you shouldn't dose Phosphorus and Iron in the same day... they can react with each other and become unavailable to plants.



Yes, I dose them at the same time. I have never heard about this interaction. Even Seachem (dose calendar fhttp://www.seachem.com/downloads/charts/Plant-Dose-Chart.pdf) recommends dosing  Iron and Phosphorus together.



kadoxu said:


> Is there a particular reason to use such expensive fertilizers?


No, currently I am just testing different brands. Seachem is interesting for me (it contains Ferrous Gluconate, urea=iminium salt, combination Flourish and Trace).



kadoxu said:


> What is the temperature of the water? How long do you run CO2? And what about lighting period?


now 25 °C (during summer it was 28 °C)
CO2 runs from 11 AM to 9 PM, lighthing period is between 2 PM and 10 PM (8 hours)



dw1305 said:


> Hi all, The iron (Fe+++) and phosphorous (PO4---) ions may have reacted together to form insoluble ferric iron phosphate complexes as "kadoxu" suggests, but it maybe the test kit. I'm not very keen on test kits, unfortunately they don't tend to be very reliable, or give repeatable results.



I also don't like test, but sometimes they help me to diagnose the problem.




dw1305 said:


> You can buy complete fertilizers mixes from one of <"our sponsors"> (other sponsors are available). Also have a look at <"The Estimative Index">.


Thanks for information about other fertilizers, I might consider trying them in the future.


cheers


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## kadoxu (26 Sep 2016)

So Seachem Flourish Iron is actually "Ferrous Gluconate"... I'm no chemist... but Darrel may know if it makes a difference.


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## dw1305 (28 Sep 2016)

Hi all, 





kadoxu said:


> So Seachem Flourish Iron is actually "Ferrous Gluconate"... I'm no chemist... but Darrel may know if it makes a difference.


 It is "_smoke and mirrors_" to some degree, the ferrous bit indicates that it is a Fe++ compound. You can tell whether an iron compound is ferrous (Fe++), or ferric (Fe+++), by the colour, black or green for ferrous, rusty red for ferric. 

Seachem will tell you that plants take up Fe++ compounds, which is true, but whether a compound is ferrous or ferric depends on pH and oxygen availability, and in the presence of oxygen ferrous rapidly turns to ferric. 

If the pH is above pH7, then all sorts of insoluble iron compounds (oxide, hydroxides, carbonate, phosphates) form.  Because it is difficult to keep Fe++(+) ions in solution, usually you use a <"chelator"> like EDTA, DTPA, EDDHA etc which slowly releases plant available iron ions over time. It might be worth noting that chelators like DTPA are quite expensive compared to Fe(II)gluconate (C12H22FeO14) .   

Tom Barr ("Plantbrain") <"posted on gluconate">. 

cheers Darrel


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