Thanks for the review, Trish.
I love and use the crystals often. I hydrate mine before adding them to the potting mix, otherwise sometimes I put too many crystals in, and when it rains hard they are flowing out. .
By the way, Watersorb is not the only company that makes these. My favorite is Soil Moist. It comes with no fertilizer, fertilizer, or Mycorrhizal Soil Additive which I think really helps plants. I've used it for years.
Here's the website for Soil Moist. Lots of neat things to do with the crystals, and there's a calculator on the page to help you know how much you need for the size container you have.
http://www.soilmoist.com/
This product you can find in garden centers, or it's quite reasonable on Ebay.