i use Soil Moist Granulas, found it at lowas in the garden section. $12 for a 1lb bag but that was 4 months ago and i have only used mab 1/200th of it! 1/8 of a tsp will suck up water and expand to fill two 32oz gadorad bottle caps. all it is is a polymer that absobs water, roachs and criks have no problems getting the water from it.