I reviewed your account and used Front Left Lawn
as an example to attempt to explain how amounts and durations are calculated. The math behind the moisture level is a bit less straightforward as it may seem. Unfortunately we cannot use direct formula of precip_rate * duration
to calculate moisture level. The way flex daily determines the amount it needs to water per zone is using this formula:
DoW = RZD * AD * AWC
where
DoW
- depth of water
RZD
- root zone depth
AD
- allowed depletion
AWC
- available water capacity
Then we determine scheduling multiplier which accounts for nozzle efficiency and uneven zone distribution using this:
SM = 1 / (.4 + .6 * efficiency)
where
SM
- scheduling maultiplier
Then duration required to water the depth of water is calculated like the following:
duration_minutes = 60 * DoW * RA * SM / PR
where
RA
- user runtime duration adjustment
PR
- nozzle precip rate (in/hr)
Based on our logs there were a few updates to advanced settings to this zone in last 30 days
one on 08/28 and few on 09/17 (today). Here is the breakdown of previous and current settings
As of 08/28
efficiency = 0.8
RZD = 4 in
AD = .5
AWC = .12
PR = 0.48 in/hr
RA = 1.50635800456472
means that duration was increased by user in schedule settings by approx. 50% from system derived duration at some point.
Plugging those into formula gives:
DoW = 4 * .50 * .12 = .24 in
SM = 1 / (.4 + .6 * .8) = 1.13636
duration_minutes = 60 * .24 * 1.50635800456472 * 1.13636 / .48 = 51.3524
Which correlates with irrigation event yesterday
Current settings
efficiency = 0.8
RZD = 6 in
AD = .5
AWC = .12
PR = 0.45 in/hr
RA = 1.50635800456472
same as before
Gives
DoW = 6 * .50 * .12 = .36 in
SM = 1 / (.4 + .6 * .8) = 1.13636
duration_minutes = 60 * .36 * 1.50635800456472 * 1.13636 / .45 = 82.165
Notice that after the zone settings update the schedule will now water 82 minutes. I hope this helps understand the calculations behind flex daily durations/moisture levels. A detailed discussion on this subject can also be found in this thread Refresh my memory on the moisture chart. Please let me know if you have more questions.