Is my apex trident broken?

[Notsolostfish]

I dosed all for reef once this morning and i noticed that my alk randomly at night went from 8.39 to 8.49 with 0 dosing. But all for reef this morning. How would thst happen

 

[Reefer Matt Verified Media Partner]

That is close to the margin of error of the machine. Also, alkalinity changes throughout the day.