Blumat sensors restrict the flow and as long as they are working fine, there's no need for these Flow Controllers. They are an inexpensive "insurance policy" though. Especially in outdoor systems where rodents, dogs, cats, high winds, and curious children can cause run-aways; these controllers can prevent floods by restricting the flow rate to one pint per foot per 24 hours. They will still keep the water going all night and when the soil doesn't need it but they will limit water use until you can reset the carrot.