Dosing Calculator

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This calculator helps you make a fertiliser solution that is used to dose your tank by calculating the ppm (mg/l) value for a given amount of solution added.
For a more comprehensive set of calculators consider

Tank Volume:
Amount to add:
Amount of water to mix with: ml

Each ml of solution that is added to your tank will add:

How To Use
1. Enter your tank volume and select either Litres, UK Gallons or US Gallons.
2. Select the nutrient you wish to use and from the chemical it is obtained.
3. Enter the amount of the chemical that is to be added to the solution and also if you are using Grams, Teaspoons or Tablespoons. This may require a bit of trial and error to achieve the desired ppm figure. Remember that only so much of a chemical can be added to a given amount of water - see table below for the amounts.
4. Enter the amount of water that is going to be used for the fertiliser solution.
5. Enter how much solution you wish to add to the tank in each dose. Some people like to add small amounts at a time like 2ml whilst others like to add large amounts like 50ml. The choice is yours.
6. Click the 'Calculate' button to display the ppm value. This is the amount that the selected nutrient will raise your tank level by.
nb. The calculator can also be used if you dose dry chemicals by putting a value of 1 in both the 'Amount of water to mix with' and 'Each ml of solution..' fields.

What ppm Values Do I Need
What amount of nutrient you wish to add depends on your dosing schedule but if dosing Estimative Index then here is a general guide:
8ppm of Nitrate which is added 3x a week
2ppm of Phosphate which is added 3x a week

Teaspoon quantities
I have calculated the amount of each chemical by weighing the amount using a standard teaspoon (5ml) which is available from most kitchen stores. Depending on where you obtain your chemicals from you may get slightly different weights. I get all mine from The Nutrient Company. Here are the weights I have used for each chemical using one teaspoon:
Potassium Nitrate 6.0g
Potassium Phosphate 6.6g
Potassium Sulphate 5.1g
Magnesium Sulphate heptahydrate 5.1g
Calcium Sulphate dihydrate 4.1g
Calcium Chloride anhydrous 3.5g

(nb.The tablespoon amount is calculated by multiplying the teaspoon amount by 3)
Solubility's In Water
There are limits on how much of a salt can be dissolved in water. As this limit is reached it becomes increasingly difficult to dissolve more. If you are experiencing difficulties in dissolving any of the salts then try doubling the amount of water it is dissolved in. Below are the maximum solubility's of the various chemicals used in the calculator.
Potassium Nitrate 36g per 100ml
Potassium Phosphate 22g per 100ml
Potassium Sulphate 11.1g per 100ml
Magnesium Sulphate heptahydrate 25.5g per 100ml
Calcium Sulphate dihydrate 0.24g per 100ml
Calcium Chloride anhydrous 74g per 100ml

This page was last updated by webmaster - 27th August 2015