Uuuugh... Can't buy dry ferts

FastFreddy

Junior Poster
Aug 27, 2010
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I have tried a number of different places in my region (Qld, Australia) however everytime I go to buy small quantities of Potassium Nitrate or Potassium Phosphate people look at me like I'm a terrorist and refuse. So I think I will need to resort to the seachem line of fertilizers.

My tank is a low tech non co2 150 gallon set up as per tom's article. My question is how I determine how much of each product (Seachem flourish nitrogen, potassium and phosphorous) to use in order to add the corresponding dosage to the fractions of teaspoons described in the article. Any help would be greatly appreciated.
 

nipat

Guru Class Expert
May 23, 2009
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Can't answer your questions but...

I heard selling KNO3 in Singapore is illegal. But it can be avoided by asking the shop
to mix KNO3 with KH2PO4.

Don't know if you can use Calcium Nitrate as an alternative.
 

pepetj

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Oct 8, 2008
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I haven't been able to find dry ferts either so I went with Seachem's liquid products that I was lucky to find locally (purchased all three NPK boxes available). In the directions of each bottle is enough information to estimate how much to add.

Thanks Pat for this tool!

Pepetj
Santo Domingo
 

ubr0ke

Prolific Poster
Aug 17, 2010
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Edmonton, Canada
In Canada your not allowed to buy potassium nitrate in its dry form but its legal to buy in smaller quantities as long as its mixed with water. So I buy 125 grams mixed with 1 litre of water. You could try to see if they will sell it like that as well.
 

FastFreddy

Junior Poster
Aug 27, 2010
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Thanks for the suggestions everyone. The same must be true here in Australia ubr0ke as I was able to find an online planted aquarium store which will send the kh2pO4 dry but said they will need to mix the KNO3 into water and send it to me in a stock solution. Now all I have to do is convert the teaspoons decribed in Tom's article into grams so I can dose in mililitres from the stock solution. I'm not very mathematically minded so I've set out my working below. If somebody could double check it for me that would be great. Thanks again everyone.

5.6 grams = 1 tsp KNO3 (as per Rex Grigg's dosing guide)

1/8 teaspoon = 0.7 grams

7.5x0.7 = 5.25 grams (7.5 was used as my 150 gallon tank is 7.5x the size of the 20 gallon described in Tom Barr's article.)

5.25 grams of KNO3 in my 150 gallon = 5.67ppm (fertilator)
 

pat w

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Nov 4, 2009
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Daphne, AL (east Mobile Bay)
475 g of KNO3 into 1000ml water will yield 5.7ppm per 10ml dose into a 135gal water column. You'll need to calculate based on less than the rated volume of the tank to allow for substrate, hardscape, plants,fish, etc.

Do you have an Excel compatable Spreadsheet app to use? If so try this - View attachment 2011

Just replace the sample data in columns "B & C"

Pat

P.S. Just let the folks you're buying it from know the 1000ml is the final volume with the full 475g.
 

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Left C

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I wrote a Seachem dosing calculator using Microsoft's Office Excel that is based on Seachem's dosing chart below. It is written in the 2003 version and the 2010 version. You can use OpenOffice.org with it as well, I believe. It is simple to use. You just enter the amount in US gallons and it gives you the amounts to dose and what days to dose as well. There are calculators for US gallons to liters and vice versa. Seachem's dosing plan is mainly for low light non-CO2 aquariums. It will save you some number crunching too. Also, since it is in Excel form, it is highly modifiable.

Excel 2003: http://www.aquaticplantcentral.com/forumapc/fertilizing/45119-seachem-dosing-calculator-chart.html
Excel 2010: http://www.aquaticplantcentral.com/...hem-dosing-calculator-chart-7.html#post565043
Making fert solutions using dry ferts that are the same ppm as Seachem's: http://www.aquaticplantcentral.com/...achem-dosing-calculator-chart.html#post336492


SeachemsPlantDosingChart.gif
 

nipat

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May 23, 2009
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FastFreddy;59546 said:
---
5.25 grams of KNO3 in my 150 gallon = 5.67ppm (fertilator)

That's correct (it doesn't need high level math at all) :)

150 US gallons is about 568 liters.

5.25 grams = 5250 milligrams

The percentage of NO3 in KNO3 is 13.854+47.474 = 61.328%.
( http://www.convertunits.com/molarmass/KNO3 )

So the amount of NO3 from 5250 mg KNO3 = 5250x61.328÷100 = 3219.72 mg.

3219.72 mg in 568 liters of water is 5.668 PPM.
 

ubr0ke

Prolific Poster
Aug 17, 2010
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Edmonton, Canada
Im not sure of the exact number but do not add more then 125 grams of potassium nitrate per 1000 ml of water for your stock solution or you will solubility issues.
 

Tom Barr

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Jan 23, 2005
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FastFreddy;59517 said:
I have tried a number of different places in my region (Qld, Australia) however everytime I go to buy small quantities of Potassium Nitrate or Potassium Phosphate people look at me like I'm a terrorist and refuse. So I think I will need to resort to the seachem line of fertilizers.

My tank is a low tech non co2 150 gallon set up as per tom's article. My question is how I determine how much of each product (Seachem flourish nitrogen, potassium and phosphorous) to use in order to add the corresponding dosage to the fractions of teaspoons described in the article. Any help would be greatly appreciated.

Look up Dave Wilson in Darwin, he sells ferts.
Aquarium life forum should provide you with resources locally in Oz.

Regards,
Tom Barr
 

pat w

Member
Nov 4, 2009
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Daphne, AL (east Mobile Bay)
ubr0ke;59585 said:
Im not sure of the exact number but do not add more then 125 grams of potassium nitrate per 1000 ml of water for your stock solution or you will solubility issues.

According to Chuck Gladd's Calculator, the solubility of KNO3 in hot distilled water is 85 g. per 100ml. That's what I based my suggestion on. If I was wrong I'll back off it.

Pat