Here are some things I've noticed about the hrc at the bottom of a sell off like that.
The best candles are long legged skinny bodied dojies.
Heavy volume is important, low volume stocks have less reliable hrc's.
You want to see the hrc, completely beneath the previous day's candle. gap downs are best.
Think about the psychology of this setup. A hollow red candle would be a white candle, the reason its hollow and red is because it closed lower than the previous close, but higher than it opened.
The first reaction is usually a knee jerk, over reaction. It gaps down. It continues to fall after the open, creating the lower tail, (the bottom is often at a historical price support level) traders step in, take the pps back up. When the traders take it up as far as they think they can get it, then the selling off takes place creating the upper wick. It's bullish, because it closes higher than the open and bounced at support.
If you start looking for them on your charts, I'm sure you will see a lot of bottom reversals with hrc's. Like anything though, they are more reliable when they coincide with price patterns and the indicators hooking up. Its about the psychology of the market and the more confident people are, the more reliable it will be.
Here is a link to the stockcharts definition of hollow candles. A white candle isn't really white, its hollow, the reason it isn't red is because it closed above the previous days close. If it closes higher than the current day's open, its hollow.
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