Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Turface. Soil Master Select, Safe-T-Sorb, Oil Dri, kitty litter.
These are all montmorillonite clays. Some are nicer colors than others. Some turn to mush sooner than others.
They will all remove the carbonates from the water. I add some coral sand to the filter (in a nylon stocking) to counteract this.
Turface: Ewing Irrigation, John Deere Landscape, other stores that sell irrigation, fertilizer and other supplies for golf, sports fields and so on. Several colors.
SMS: No longer available.
Safe-T-Sorb: Tractor Supply, sold for soaking up oil and other fluids especially in automotive repair, but other similar uses, too. Soft tan and grey.
Oil Dri: The Smart n Final near me carries it, and I would sure check out automotive stores. White or off white.
Kitty Litter: Research here to see which brands have worked. White or off white.