A custom amount that changes each time is very difficult. If the amounts are more consistent, I do that for priming and stuff on mine.
The way you do that is set up a profile of type DOSE with the amount you want, speed I usually set 250ml/min so it happens fast and interval set to 1. Let's call this primeDOS as an example
Create a virtual outlet with the following code. Change MMM:SS to an value longer than the dose would take (ex larger than 2 minutes for a 500ml dose). I'm calling this prime.
Interesting. So I need to dose like 1-5ml So I would set up the dos speed super low right?. Then if I wanted to dose I would just do if its 1ml/5sec just do
Set ON
When ON >000:10 Then ON
that would give me 2ml?
Realistically I should just manually dose this since its Nitrates and Phosphates lol