When you use any indicators you suffer of lagging and possibile mistakes. In this case, higher movements of the (daily) prices (long green candle) are a signal that market is appreciating your stock. The variation of a single candle is compared to standard deviation of the stock. Besides normal money management (on fixed percentages), we have kept the possibily of exiting the position before stop loss adding a multiplier considering that red (or black) candles are normally wider than green (white) ones.