Explanation for the 8ms delay :
https://forums.adafruit.com/viewtopic.php?f=25&t=50446
Those are derived values.
The ADS1x15 family of ADCs have an ALERT/READY pin that generates a pulse when each conversion is complete, but using that consumes a microcontroller pin and an interrupt service routine. Instead of using that, we wrote the library to wait for a fixed amount of time for the conversion to finish.
The ADS1015’s maximum sampling rate is 3ksps, so a 1ms delay (corresponding to a rate of 1ksps) strikes a balance between simplicity and guaranteed success of getting a conversion. The ADS1115 can do 860sps, and our default delay takes the rate to 125sps.
So I need to change the SPS to the max 860 and reduce this to 1ms