Tapered candle issue still.

Question

The candle holder is secured in another holder, no problem with it. As the candle, in the water, burns and gets shorter and the bottom of the candle gets closer to the larger opening of the holder towards the top, that is when the candle wants to tobble over when it is 5 or 6" long.

Answer 1

Thanks for the detail.  Seems like you need to somehow reduce the diameter of the candle passage in the top area.  While it would be easier to imagine if I could see the glass holder, I am thinking about a large washer/donut shaped insert, the center hole big enough for the candle, the outer edge big enough to lodge or sit in the wider part of the glass holder.  Could be made of wood, plastic, anything firm.