How about thes? Water Absorbing Polymer Crystals, Aqua Crystal Earth - eBay (item 130194579363 end time Feb-06-08 15:43:12 PST)

Would those work as the polymer crystals you said you need?
ManOHman Reviewed by ManOHman on . How to build your own inexpensive odour neutraliser Bad smells, stink and hefty weed odours is something every indoor cultivator needs like another hole in the head. Because the problem arises as a result of growing activities, it is logical to take preventative measures. Many weed growers use carbon filters to get rid of weed smells and that can often be expensive, depending on the size of your space, of course. For those starter growers and other interested parties, investing in ventilation and filters can be a big step and Rating: 5