Sand

[SoLiD]

you can make mineral mud for about 4.00 making it a lot cheaper than buying it. if you go that route go to petco and get a bag of cat litter. it is dr something or other natural cat litter 100% clay. make sure it says that. soak it and then add and in about 6 months the same stuff as mineral mud.

Does the kitty litter have iron in it because some parts of mineral mud stick to a magnet which would indicate iron. Let us know which kind of kitty litter to use & if you have done it already.