For all the marbles

[subbrew]

This a repost as it seems this post was lost.

Since I may never get around to breaking and sifting lava rock to get 1/4 to 3/8 inch rock to put into a column I decided to see about using marbles. To see how much I needed I bought 500 3/8 inch marbles. 500 3/8 inch marbles fill a 3 inch column just a bit less than 4 inches. So to fill a 60 inch column will take about 7500 marbles (about $150 worth) by the time you assume a couple inches for some wires and copper mess at the bottom. So if you have been thinking about marbles and wondering how many you need, this should start you.