Math. Let's do math!
First I took a baseline reading of my filtered water. It sits at .485 ec (after pH)
That's rather high. Probably will invest in a RO system at some point.
Next, let's look at nutrients and measure the change in ec per mL per gal.
Micro - .17
Gro - .0935
Bloom - .0755
Next, set target ECs for different stages (may need future adjustment, but let's pick something and go with it for now, then let the plants decide)
Seedling 0.5-0.7
Early veg 0.8-1
Veg 1.1-1.2
Transition 1.3-1.4
Flowering 1.6-1.8
Now, knowing EC delta and targets, we can easily calculate optimal nutes based on the recommended ratios (mL/gal)
Stage Mic Gro Bloom
Seedling 2.0 2.0 2.0
Early veg 2.5 2.5 2.5
Veg 3.2 4.8 1.6
Transition 4.0 4.0 4.0
Flowering 5.0 2.5 7.5
At least in theory! I'm hoping to develop a formula where I can micro-adjust nutes based on base EC of the water and plant reaction to feedings. Then, should I need to do a +/- EC for a res change I can plug in numbers and go.
After a week and a half of listening to the plants, this batch is most happy around 1.5 EC, so I'm feeding at just under that with the following formula:
Micro: 3.75/gal
Gro: 1.88/gal
Bloom: 5.63/gal
I have stabilized pH and EC now at 6.0/1.5, feeding at 1.45 which means the plants are happy