Flex Schedule Zone to Keep Pool Full

I need some help please.

The Iro allows for 10 evapotranspiration related parameters to be specified to get automated, no mess no fuss, never touch it again perfect watering of landscape zones down to perfection, no matter what the weather is, temperature, rainfall and all, all year round:

Plant material, soil, slope, shade, type of sprinkler head, area, avail water, root depth, allowed depletion, and efficiency.

This is the beauty of a Flex Scheduled zone. Never again waste a drop of water - it’s all optimized.

What I need is a translation of these 10 parameters, to set up one zone, Flex Scheduled, to this:

5 minutes of watering, daily, in the month of July, in the Dallas area, when the sky is clear and it’s bright, sunny and hot.
1 minute of watering, daily, in the month of Jan., when the sky is clear and it’s bright, sunny and cold.

When it’s raining I don’t want water. When it’s cloudy I want less water. When it’s hot and dry I want more water (up to the max of 5 minutes). When it’s cold and damp I want less water. Etc. Not one thing different than what Flex Scheduling already provides for.

What I want is the water amount adjusted exactly like a Flex Scheduled zone is supposed to do. What I can’t figure out is how to specify the 10 parameters such that I get 5 min per day in July and 2 min. per day in Jan. as described above.

I have extreme trouble translating all of the 10 landscaping parameters to minutes per day. It’s bewildering. But I’m not a landscape expert and I don’t understand evapotranspiration concepts at all.

Is there someone here who is really smart with all of these ten evapotranspiration parameters that can simply tell me what to set all ten parameters to that will give to me the watering per day asked for here, adjusted no differently than any other zone would be for weather changes?

Huge thanks!

Best regards,


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Man, I hate to sound like an insensitive a-hole, but you are trying to cook soup in a toaster. The transevap is going to be higher than evaporate no matter what plant type because of metabolic processes.

The solar radiation coefficient is not ever going to line up with soil types either.

I could be wrong but I think they would have to provide a pool model, because surface area is going to have a much larger effect when combined with number of ppl in the pool, water depth, water temp, wind speed and relative humidity.

If I were doing this myself, I would codify http://m.hpac.com/humidification-dehumidification/simplified-calculating-evaporation-1011 into openhab, demoticz or your automation tool of choice because you are going to find too many edge cases for a fire and forget solution.

Of if looking for something easier and more ghetto, use sensors to detect current level and refill until sensor indicates full at like midnight or 3 am.

But hopefully someone shows the errors of my ways so I can learn something.

Please allow me to simplify:

I simply want a flex scheduled zone to get me about 5 minutes daily of watering during the heat of the summer in ZIP 75074 (Dallas area).

You may ask why not just use a timer scheduled zone. The answer is I want to take advantage of watering adjustment based on actual weather conditions. I don’t want 5 minutes on the day of a rainfall, or the next day after it has rained, or when it’s a cloudy day, or when it’s a colder day.

This is my biggest reservation about the Rachio. It’s very difficult to translate desired watering pattern into the ten adjustable controller parameters. A lady on the tour last Fall said “I just want to water my flowers every third day for about 30 minutes. Can I do this?” I said I’m sure it’s possible but at the moment the interface is too complicated for most to figure out how to do this.

I wish there was a conversion app on Rachio’s site: put in amount of water desired daily during hottest part of the year (i.e. 15 minutes), put in frequency of watering desired (i.e. every day, every other day or every third day) and put in ZIP. Out comes the values for the 10 parameters the Iro needs to do flex scheduling (soil, slope, shade, type of head, area, avail water, root depth allowed depletion and efficiency).

Thank you.

Best regards,


turn off smart cycle on this zone.
sand as the substrate, im assuming that they account for a quicker movement of water through the soil, thus a lower field capacity, thus it will have some effect on the frequency of watering. in a normal setup, the soil type will have a much lager impact on the smart cycling feature…but im making an assumption here, @franz?

here is how you adjust the frequency of watering the most, select annuals for the zone since it has the highest te coefficient to start. if watering too frequently (probably will not be your problem) then select a vegetation type with a lower te coeffecient. my annual zones ran pretty much every day in peak heat.

here is the fine tuning on how long it runs, make a custom head that is really high for that zone. then check your watering. if running too long, make the gpm of the head smaller…else make it bigger.

remember, you make very fine adjustments of the runtime duration in the flexy itself.

having said all of this, my prediction is that you will spend a lot of time fine tuning flexies accounting for natural precipitation. i feel you will find that you must adjust every parameter listed above to more effecively account for natural percip. you might be tempted to fall back to ifttt recipe that imposes a 2 day rain delay if percip is above a certain point, but i feel the rest of your vegetation will suffer as a result.

god speed homie!

root depth will effect how long a zone waters and available water/allowed depletion will effect the frequency of runs on a zone. honestly, how i dont know how i would map those onto your situation because their concepts do not apply here, you can use these to make even finer adjustments but with transient effects.

I can’t find where Smart Cycle can be turned on/off by zone - only by schedule. Bill

Thank you.

Here’s my starting point:

Annuals, in Sand, on Flat slope, getting Lots Of Shade, using Bubblers, for 100 SF, with 0.05 Avail Water, a Root Depth of 4", an Allowed Depletion of 50%, and 100% Efficiency.

With these 10 parameters, for my ZIP (75074), at this time of year, I’ll:

  • average about 0.045" daily of Crop Evapotranspiration
  • put down 0.10" of irrigation when irrigation is triggered
  • in 3 minutes of time
  • and run every day.

OK. Good starting point.

Now I’ll work on reducing the 3 to 2 minutes.

Now I need to figure out what to change to reduce down from 3 min. per day.

Best regards,


Change out your bubblers with ones that have twice the flow rate? That would get you down to 1/2 the time, but why do you need to go down from 3 minutes?

I don’t know what’s meant by “change out your bubblers …” Can you translate? I simply selected one (bubbler) of the six options for one of the ten parameters (nozzle type).

I want less water per day at the moment because it’s winter time and I thus don’t need as much water daily to keep up with the evaporation of water.


Best regards,


Make a custom,head with a higher percipient rate for the zone, unless you are running into a floor in the code.

I am also in the Dallas area and have a zone that is dedicated to pool fill. I put that zone on it’s own schedule so that I can easily adjust it.

Settings in the controller can’t change the flow rate of your zones, the amount of water put down is controlled by duration. If you want a shorter duration make your custom nozzle have a higher precip rate.

Maybe I’m misunderstanding the question?

That’s the beauty of FLEX schedules … if you have fairly accurate ET data then you should not have to mess with any settings since in the winter there is less evaporation so your schedule should run less frequently.

I can’t tell, I can’t tell if you recommend changing physical bubblers or if you are implicitly referencing the head type for the zone in the software

I am using a Flex schedule, and is what I want to do. Maximum watering during summer time, minimal watering during winter time, all adjusted automatically depending on weather conditions.

For this one zone, I have too much water coming out (3 minutes) now, and noting I’m using Flex scheduling I’ll have too much water coming out of the zone in the Summer. Think of it like I’m ‘flooding the zone.’

At the moment, for my ZIP (Dallas area) my average daily Crop Evapotranspiration is about 0.045".

The result of the 10 settings you can change for a zone, noting my ZIP, is 3 minutes daily of Zone On time at the moment.

I want to bring this down to 2 minutes daily - I’m flooding the zone every day.

So far I’m unable to figure out how to do so. I tried implementing a ‘custom head’ but wasn’t able to figure out how to do it.

Thank you.

Best regards,


I was recommending changing out the actual bubblers on his irrigation system. Bill asked how he could:

Less time = less water unless you up the flow of the sprinklers.

One quick way to reduce water on that zone ( without creating a custom nozzle ) would be to reduce your root depth or increase your allowed depletion value.

ronjonp: you are my hero today!

I cut in half my root depth, from 4 to 2". This changed my Zone ‘On’ time from 3 to 2 minutes (from 0.10 to 0.05" irrigation), and left alone my frequency to continue daily. Awesome!

For those of you with pools, that don’t want to waste any water by putting in more than needed daily to ‘top off’ the pool due to surface water evaporation to the atmosphere, here are my settings that look to deliver about 2 minutes daily for ZIP 75074 in the month of Feb:

1-Growing Annuals
2-In Sand
3-On Flat slope
4-In a Lot of Shade
5-Using Bubblers
6-Covering 100 SF
7-Avail Water 0.05"
8-Root Depth = 2" (changed from 4")
9-Allowed Depletion = 50%
10-Efficiency = 100%

Thanks for the help!

Best regards,


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Glad you got it sorted :smile:

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You could also put together a recipe that started on a certain date & made a 50% seasonal adjustment for your bubblers ( likewise to reverse ), then you don’t have to think about it in the future :smile:

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I had no idea you can make seasonal adjustments on a flex schedule. Learn something new everyday

Report back in the summer, I’m curious. I think by reducing your root depth you have reduced the volume of the “tank” so I’m curious if the flex schedule will be able to keep up during peak heat.

The schedule can’t run more than 1 time a day, and flex schedules do not increase/decrease their run time, only their frequency, so it feels like you need your schedule to run less frequently during cooler times with more volume so that it can increase that frequency during peak heat to keep up with the evaporation of your pool thus you will be able to find the most tolerable ebb and flow.