This is an example of a scrolling graph driven by a Clock Timer and a random number generator:
(from FAQ Section: Charts and Graphs)
The basic idea is to check the number of graph entries each time you add a new entry, and once you pass the minimum number you want to keep, remove the oldest.
For BLE, instead of a Clock Timer you would drive this by the Received event(s) for your ADC data, in a FOR EACH loop to traverse the incoming list of ADC readings.