I guess I'm a bit confused about what it is that you are trying to accomplish. In order for James calculator to work you have to fill in the grams or teaspoons and the amount of each dose.
I'm also not clear on why teaspoons are so difficult if you are making up a one month or two month supply. Here is a direct quote from the article regarding a 20gallon tank. all you have to do is multiply the numbers by 3 for a 60 gallon tank:
NPK (Nitrogen+Phosphorus+Potassium) Mixture for 20 Gallon Tank
1 month = 4 Weeks
3 doses of NPK per week
Therefore there are 12 doses of NPK per month.
Multiply a single dose teaspoon value by 12 => [3/16 tsp KNO3]*12 =
2 Â¼ tsp KNO3
--------------------------------------------------[1/16 tsp KH2PO4]*12 =
Â¾ tsp KH2PO4
---------------------------------------------------[1/2 tsp MgSO4]*12 =
6 tsp MgSO4
Add these to 600ml of tap or distilled water
Now this mixture must serve 12 doses so each dose is 600ml/12 = 50ml
This makes life easier because you need only dose 50ml of this NPK solution 3 times per week.
For your 60 gallon tank multiply the blue numbers by 3 and round off. You then get:
7 tsp KNO3
2.5 tsp KH2PO4
18 tsp MgSO4
Add these to 600ml of water and each dose is 50ml
If you use 500ml of water each dose becomes a weird number 500/12 = 42 ml.
If you have trouble dissolving the powders just double the amount of water to 1200ml and each dose becomes 100 ml.
Now I don't see why there should be such a phobia regarding counting 7 teaspoons of KNO3 or why you would need a gram scale to do conversion.
Cheers,