# dosing question



## rickwaines (Jan 2, 2011)

I am dosing macro and micro plus excel, all seachem. A couple times a week each. The plants seem to be responding so all seems well but I am wondering how one protects against overdoing it. I do 25% water changes once a week. Is that enough to protect against overdosing this or that? Are there test kits available for potassium phosphate and nitrogen? I know the EI approach is supposed to make it so you don't need to test but I guess I am wondering if others have experience to offer.

Thanks, Rick


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## neven (May 15, 2010)

math is how! but for us who suck at it, or prefer not to think, rest assured, there is a place that lets you know!

Concentrations of Stuff vs Time and Plant Uptake using The Estimative Index

It works for all types, the seachem should tell you just what you are adding

found this on tom barr's site in this thread
http://www.barrreport.com/showthread.php/7234-Wet-s-EI-modeling-dosing-calculator


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## davej (Apr 28, 2010)

This is a great post to read thru regarding EI dosing.
Should answer a lot of questions.

_Dosing Regime's_


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## neven (May 15, 2010)

davej said:


> This is a great post to read thru regarding EI dosing.
> Should answer a lot of questions.
> 
> _Dosing Regime's_


^^ Excellent thread, helped me a ton when i first started EI dosing


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## 2wheelsx2 (Apr 21, 2010)

I used the same dosing thread when I started EI. Essentially if you do the bigger water changes though 50% or more, then the EI system works in that you never elevate above a certain level. With smaller water changes, there is a chance to overdose for short periods. I did test for nitrate and phosphate in the beginning and that's when I figured out I never have to dose for phosphates when I'm feeding pellet food.


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## rickwaines (Jan 2, 2011)

Thanks all.

The dosing calculator was a bit confusing perhaps it will take another look. The seachem bottles say that I am dosing about 3 ppm total "stuff" per dose. The calculator then displayed a somewhat confusing graph that I wasn't able to interpret. I am struggling with the great unkown in the tank. I guess I might like to acquire some test kits as the mystery of what I have in the tank as far as macro nutrients is killing me. There is a test for phosphate but are there tests for nitrogen and potassium or are there other ways to glean this info.

Rick


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## 2wheelsx2 (Apr 21, 2010)

I don't use a K test kit, but you test for N with the nitrate test kits, as that's the only one you'll be able to measure (the other forms will be converted by your bio filter). If you're dosing KNO3, that's usually enough K anyway. I just had a look at the Seachem Flourish Nitrogen ingredients and it uses KNO3 has the nitrogen source anyway. Also contains potash (K2O) so you should have plenty of K.


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## neven (May 15, 2010)

the graph requires you to assume how much uptake you have from your plants, ie how heavily stocked your plants are. it'll take a bit to figure out your plant load but since you know how much ppm you are dosing, testing nitrates before water change can let you find where you stand on the chart


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## EDGE (Aug 24, 2010)

Ignore the word "potash" as a chemical composition. Potash is actually derived from the potassium in kno3. They have to use potash (K2O) instead of Just potassium (K) to show how much potassium is in the liquid.

Urea is part of flourish Nitrogen though. 

The ratio is for Nitrogen and not nitrate. nitrate is roughly 4.4 times the number for nitrogen.


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## 2wheelsx2 (Apr 21, 2010)

EDGE said:


> Ignore the word "potash" as a chemical composition. Potash is actually derived from the potassium in kno3. They have to use potash (K2O) instead of Just potassium (K) to show how much potassium is in the liquid.
> 
> Urea is part of flourish Nitrogen though.
> 
> The ratio is for Nitrogen and not nitrate. nitrate is roughly 4.4 times the number for nitrogen.


I had assumed that the formulation is potash based, hence the potash reference. So Seachem is using soluble potash to express how much K is in the mixture? Seems kinda backwards. Anyway, that's good to know, even though I'll likely not buy the liquid ferts any time soon.


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## rickwaines (Jan 2, 2011)

I will likely switch to the dry ferts soon for obvious reasons.


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## rickwaines (Jan 2, 2011)

neven said:


> the graph requires you to assume how much uptake you have from your plants, ie how heavily stocked your plants are. it'll take a bit to figure out your plant load but since you know how much ppm you are dosing, testing nitrates before water change can let you find where you stand on the chart


ahhh, the 4 different colours depict different plant loads. Check, it makes more sense now.


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## EDGE (Aug 24, 2010)

no, not seachem.. The fertilizer act required any and all company to represent K in the form of potash and P as P2O5. This goes for Canada as well as the United States.

When we go to look at the ratio or % of the NPK in commercial product. i.e. 20-20-20, this is in N-P2O5-K2O. and not N-P-K or NO3-PO4-K..


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## rickwaines (Jan 2, 2011)

2wheelsx2 said:


> I don't use a K test kit, but you test for N with the nitrate test kits, as that's the only one you'll be able to measure (the other forms will be converted by your bio filter). If you're dosing KNO3, that's usually enough K anyway. I just had a look at the Seachem Flourish Nitrogen ingredients and it uses KNO3 has the nitrogen source anyway. Also contains potash (K2O) so you should have plenty of K.


so, sorry for my opaqueness but my nitrate levels are representative of how much nitrogen is in the system. For example, with the api test kit I currently have 7 ppm nitrate. I should use this to determine my need for nitrogen supplement.

And as far as, "I should have enough K" Is there a point when I could have too much K?


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## rickwaines (Jan 2, 2011)

EDGE said:


> Ignore the word "potash" as a chemical composition. Potash is actually derived from the potassium in kno3. They have to use potash (K2O) instead of Just potassium (K) to show how much potassium is in the liquid.
> 
> Urea is part of flourish Nitrogen though.
> 
> The ratio is for Nitrogen and not nitrate. nitrate is roughly 4.4 times the number for nitrogen.


so, if my nitrate is 7 by an api test kit I should divide that by 4.4 to get the nitrogen in the system?


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## rickwaines (Jan 2, 2011)

EDGE said:


> Ignore the word "potash" as a chemical composition. Potash is actually derived from the potassium in kno3. They have to use potash (K2O) instead of Just potassium (K) to show how much potassium is in the liquid.
> 
> Urea is part of flourish Nitrogen though.
> 
> And how is urea is relevant in this?


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## EDGE (Aug 24, 2010)

rickwaines said:


> so, if my nitrate is 7 by an api test kit I should divide that by 4.4 to get the nitrogen in the system?


Technically yes, but in aquarium, most measurements are done in NO3 nitrate and not nitrogen. and 10 ppm NO3 is plenty for plants in most cases.

When using terrestrial base fertilizer, just have to becareful how much to add.


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## rickwaines (Jan 2, 2011)

it is all starting to make sense. piece by piece. Nitrate gets divided by 4.4 to get the nitrogen. check


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## davej (Apr 28, 2010)

One of the beauty's of EI is because you are doing a 50% water change every week the levels of your Macros are getting reset every week. Its been a few years since I had the full-on planted, but the whole idea is that you don't need to test for your levels, as long as you are sticking to the recommended doses then you don't need to worry about the exact levels. You are just making sure that the plants have the needed nutrients available all the time.


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## EDGE (Aug 24, 2010)

rickwaines said:


> And how is urea is relevant in this?


Bascially, Urea helps increase the Nitrogen level while keeping potassium at a minimal. Plants in general uses way more nitrogen than potassium unless they are fruiting. potassium nitrate, in some cases, add more potassium into the water column than needed. This is where resetting with 50% water change helps. Don't have to worry too much about the science behind fertilizing and focus on the hobby itself ^_^.

I started using ammonium nitrate a while ago to help offset the old depleted ADA soil.


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## davej (Apr 28, 2010)

Another invaluable resource is,
Aquarium Plants - Barr Report - Subscribe to the Barr Report
Surf around a little and a lot of questions will be answered. 
Plus you will probaly have a few new question tht you never considered as well.


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## neven (May 15, 2010)

I wouldn't worry about too much K, for a time it was considered that increasing K was the solution to everything. You definately wont be dosing K to a point where it would have negative effects, but the EI recommended levels are meant to dose it to a point where more would be a waste of nutrient.

One of the main reasons Kno3 is used is because it will provide enough K for medium light moderate plant load tanks on its own.

The EI system was created by tom barr to really simplify things compared to how things were. I believe the poor man's dosing drop method was the norm prior.


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