I'm not 100% sure how well you know candlestick charts, so I'm assuming you know less based on your question but forgive me if you already know this stuff. With the solid bars vs empty bars, those are normal for a candlestick chart, although google charts has it backwards to other charting software for some reason, something I'll also look into - usually a lighter or green bar represents a rise in price from opening time to close in the charting period (15min is the total time period per bar in this chart's case), and darker or red for down. The bars are supposed to represent the difference in open and closing price in the chart period (the solid bar bit) and the lines coming out of the bars are the high and low during the 15 minute period, where the price reached but didn't remain.