Generally with your lighting, it can last a few months.
Lighting is what drives the need of Co2 and Ferts
As with dosing, you can try the two more popular methods in this hobby. PPS-Pro
or EI (Estimative Index)
that was invented by Tom Barr (plantbrain on the forum).
I've used both and personally I prefer PPS-Pro as I'm a junior in high school and I don't have the time to dose daily. Setting up an autodoser (also viable with EI) and not doing water changes is the way to go with me