At this point the ladies have been on a reformulated feeding program for about a week. Here is the link to my thread about the nutrient profile:
https://www.rollitup.org/advanced-marijuana-cultivation/322450-lucas-formula-dyna-gro-cannatari.html
As the thread explains, my new formula is based on 2 cannabis nutrient profiles. One discovered by Mel Frank and the other by PHimbalance. Their results were simplified into a 2-part GH formula made famous by Lucas. My mission was to imitate Lucas's General Hydroponics Formula using the Dyna-Gro line of nutrients. Henceforth this journal will track the progress of the Lucas Formula using Dyna-Gro. I will stay true to the Lucas Formula by:
1. Using only the formula, no supplements.*
2. Making no resivoir changes from start to finish using the add-back method.
3. Make no Ph adjustments as long as it's fluctuating within 5.3-6.3.
*I will be flushing with molasses. If I get that far I will have already determined the formula is satisfactory.
My recipe is: 5ml Grow, 5ml Mag-Pro and 10ml Pro TeKt per gallon, also expressed as 1:1:2.
Here is an example of the add back calc I'll be using:
((Target ppm - Current ppm) / Target ppm) x ml's per part, per gallon x Resivoir Capacity = ml of nutes to add to res.
The Target ppm is the ppm of 1 gallon of freshly mixed nutes.
The Current ppm is the ppm of the resivoir after being topped off with plain water.
So....
((1200-960)/1200)x5x8= ml of nutes to add
(340/1200)x5x8
.283x5x8=11.3ml
Using my 1:1:2 (5ml:5ml:10ml) recipe I add: 11.3 ml of Grow,11.3 ml of Mag-Pro and 22.6 ml of Pro-TeKt to the resivoir. This should be the correct amount of nutrients I need to add to an 8 gallon resivoir to bring it from 960ppm to 1200ppm.
Now by using this chart:
I should be able to fine tune things based on extreme ph fluctuations and add or subtract relative amounts of N-P-K ratios in the formula till the ph fluctuates in the desired range, 5.3-6.3. So far the ph in my veg res went up while the flowering res ph went down within a couple of days of switching to the new formula. I had to adjust the veg res but not the flowering res which is holding strong at 5.7-5.8, down from it's original 6.1. Note that I only intend on using the new formula for flowering plants but will use the same approach to fine-tune my veg nutes. Fingers X'ed.