It's not quite DIY but I got some really great rock from thesehttp://www.hirocks.com/Index.html guys. Lots of holes very porus, I am using it for the base in my 65.
I plumbed a 32 gal trash rubbermaid trash barrel to hadle the RO/DI waste water. It is elevated in a corner of my basement by the washing machine, I ran some 1/2" PVC from it to the wall by the washer. There is a valve and a few feet of flexible tube. I also added an overflow and plumbed it to...
