I should mention that the media can be recharged 4-5 times. I had used it one month or so and never "charged" it again. I think you just soak in baking soda.
So it should be recharged now and then should last 6-12 months depending on how much phosphate is in your water. I think they recommend soaking it every two months though.
http://www.jlaquatics.com/product/pl...r+-+300ml.html