I've added the ability to set alerts when each or any of the candles change colour. There is also an alert option if all the candles become the same colour, so you can use that to identify a really strong trend. (or the possibility that the trend could be about to reverse!)
When you create an alert on this indicator, in the Create Alert settings, use the 'Any alert() function call' dropdown menu to select which candle that you want to set the alert for. Each candle will require a separate alert to be set for it.