Hi Elisabeth,
Netro will skip smart watering and programs when there is large amount of rain or watering regulations and manual restrictions. So when you set up your own program watering time, please do not conflict with your local Regulations if there is any.
Could you please send us email to support@netrohome.com with your Netro account registered email? Which zones did Netro skip watering with program settings watering every three days?
We will have our technician look into this issue.
Thanks,
Wency
Netro Support