The decision was made after 3 summers to retire the MEMS swamp cooler on the 4th summer.  The manetenance of the peristalsis pump, water level sensor, & transducers was pretty intense.  Swamp coolers arrived in summer 2021.  The 1st hygrometer arrived in summer 2022, revealing the ambient humidity to be much higher than expected.  It might be the landscaping.  The swamp cooler was only effective below 30% humidity.  The apartment was normally above 30% even on the hottest days.

The arrival of the motorized HDX sprayer in 2024 was the final development which ended the MEMS.  Younger lion didn't realize how much heat he generated pumping a manual sprayer.  Automating it made water sprayers more effective than any MEMS system could ever be.   Even below 30%, the HDX sprayer blew away anything the swamp cooler could do.

Running the swap cooler overnight might have reduced the temperature only 2 deg, but it added a lot of humidity.    If it was below 30%, the ambient air cooled down on its own.  If it was above 30%, the ambient air didn't cool down but the swamp cooler was useless.  It had to be turned off in the morning to try to reduce the humidity.  It also deposited scale on everything.