What does the VG/PG precedence option do?
To answer your question about PG/VG Precedence a long explanation is needed.
If enough PG or VG cannot be added to a recipe to meet the requirements of a recipe the “PG/VG Precedence” tells the calculator which of the two percentages it should fill first. This setting is important when you have the “Tools->Options”, General tab, “Volume Calculation” checked.
When “Volume Calculation” is unchecked the calculator functions like most other calculators. The PG/VG ratio reflects the percentage of PG and VG based on the total volume of PG and VG in a recipe. When “Volume Calculation” is checked, the PG/VG ratio reflects the percentage of PG and VG based on the total volume of the recipe (all ingredients, not just PG & VG based ingredients). This will become more clear with an example.
Example (using extreme values to make the point)
1. You are making a recipe of 100 ml.
2. Your recipe is calling for 50 ml of ingredients that do not contain any PG or VG (distilled water for example).
3. Now the calculator has to figure out how much PG and VG to add to make 100 ml. You requested that the recipe be 50/50 PG/VG.
With “Volume Calculation” unchecked the calculator will tell you to add 25 ml of PG and 25 ml of VG. Total PG/VG volume is 50 ml and 50% of 50 ml is 25 ml. Your recipe is 50/50 PG/VG.
With “Volume Calculation” checked and “VG Precedence” checked, the calculator will tell you to add 50 ml of VG. Total volume of the recipe is 100 ml and 50% of 100 ml is 50 ml. If any PG is added to the recipe you will exceed the 100 ml therefore the amount of PG to add is 0 ml. The resulting recipes PG/VG percentage will be 0/50 PG/VG. Now if you click on “PG Precedence” the resulting recipe will be 50/0 PG/VG.
Other notes related to volume calculation:
- With it unchecked, the requested PG + VG must always be 100%.
- With it checked, the requested PG + VG does not need to total 100% (but can’t be more than 100%). Using my example above you could request PG = 25% and VG = 25%. This would give you the same resulting recipe that you get with it unchecked.
I have my calculator setup with the “Volume Calculation” checked. I want to know the actual percentages of PG and VG in my recipe. Have you ever had a recipe that was 20/80 PG/VG and you wondered why it wasn’t as thick as you expected it to be? In my opinion; the standard that has been established is flawed. The standard is that PG + VG must always equal 100% even if the recipe has other ingredients that are not PG and VG based.