There is no science about the issue at hand. It is impossible to generate 40% waste nutes by fertigating to 20% runoff, whether it is done 1 time or 50 times a day. The arithmetic is simple. The percentage figure normally used is runoff divided by fertigation volume. Total runoff for the day divided by total input for the day will still be 20% at the end of the day - not science, just straight arithmetic. It appears that the calculations that I am familiar with are not being used. I would love to see numbers to clarify what the 40% actually means.
Ok hour by hour we will use a 5 ounces input each time the pump comes on and 16 ounces needed to start run-off This will be my actual schedule on the 8/4 8/4 I have 4 water cycles available for each lights on period.
Midnight to 1 am is a lights Off hour
1 am to 2 am is a lights Off hour
2 am to 3 am is a lights Off hour
4 am to 5 am is a lights On hour with continued dry back
5 am to 6 am is a lights On hour with continued dry back
6 am to 7 am is a lights On hour with a 5 oz. fertigation no runoff observed.
7 am to 8 am is a lights On hour with a 5 oz. fertigation no runoff observed. 10 oz fed so far
8 am to 9am is a lights On hour with a 5 oz. fertigation no runoff observed. 15 oz fed so far.
9am to 10 am is is a lights On hour with a 5 oz. fertigation no runoff observed. 20 oz fed with 4 oz of run-off observed 4oz is 20% run-off total.
10 am to 11 am is a lights on dry back hour
11 am to Noon is a lights on dry back hour
Noon to 1 pm is a lights off hour
1 pm to 2 pm is a lights off hour
2 pm to 3 pm is a lights off hour
3 pm to 4 pm is a lights off hour
4 pm to 5 pm is a lights On hour with continued dry back
5 pm to 6 pm is a lights On hour with continued dry back
6 pm to 7 pm is a lights On hour with a 5 oz. fertigation no runoff observed.
7 pm to 8 pm is a lights On hour with a 5 oz. fertigation no runoff observed. 10 oz fed so far
8 pm to 9 pm is a lights On hour with a 5 oz. fertigation no runoff observed. 15 oz fed so far.
9 pm to 10 pm is is a lights On hour with a 5 oz. fertigation no runoff observed. 20 oz fed with 4 oz of run-off observed 4oz is 20% run-off total.
10 pm to 11 pm is a lights on dry back hour
11pm to midnight is a lights on dry back hour
Midnight to 1 am is a lights off hour.
That concludes the 24 hour day with 8 oz of run-off
When I run 18/6 this is the schedule. I have 14 hours between the dry back periods in which to use 8 watering times to complete a 20% run-off total.
Midnight to 1 am is a lights On hour
1 am to 2 am is a lights On hour with a 2.5 oz fertigation no runoff observed 12.5 oz total
2 am to 3 am is a lights On hour
4 am to 5 am is a lights On hour with a 2.5 oz fertigation no runoff observed 15 oz total
5 am to 6 am is a lights On hour
6 am to 7 am is a lights On hour with a 2.5 oz. fertigation 1.5oz runoff observed. 17.5 total
7 am to 8 am is a lights On hour with a 2.5 oz. fertigation no 4 oz runoff observed. 20oz total 20% run off total
8 am to 9am is a lights On dry back hour
9am to 10 am is is a lights On dry back hour
10 am to 11 am is a lights off hour
11 am to Noon is a lights off hour
Noon to 1 pm is a lights off hour
1 pm to 2 pm is a lights off hour
2 pm to 3 pm is a lights off hour
3 pm to 4 pm is a lights off hour
4 pm to 5 pm is a lights On hour with continued dry back
5 pm to 6 pm is a lights On hour with continued dry back
6 pm to 7 pm is a lights On hour with a 2.5 oz. fertigation no runoff observed.
7 pm to 8 pm is a lights On hour with a 2.5 oz. fertigation no runoff observed. 5oz total
8 pm to 9 pm is a lights On hour
9 pm to 10 pm is is a lights On hour with a 2.5 oz fertigation no runoff observed 7.5oz total
10 pm to 11 pm is a lights on On hour.
11pm to midnight is a lights On hour with a 2.5 oz fertigation no runoff observed 10 oz total
Midnight to 1 am is a lights On hour.
This concludes the 24 hour cycle with 4 oz of run-off
So at the end of the day I get twice as much run-off on the 8/4 8/4 schedule compared to the 18/6 in a 24 hour period.