never heard of it but google found an answer from a review :
The biggest downfall for Aqua Parm's Purifier is that the cartridges are fairly expensive, running at $19 a piece when I was buying them. I would get a lot of water out of though, normally around 280-300 gallons of water. That was about 28-30 water changes for my 55 gallon tank. That's about the same as a bucket of salt will last you. Not bad though when you think about. Also, the cartridges are rechargeable, though Aqua Parm won't tell you that. It's a rather advanced hobbist thing to do though and can be dangerous if you aren't careful, but I know a couple of hobbists on the reefcentral.com board that will recharge cartridges for people for free. It makes sense that it is rechargeable, as many top of the line RO units include the same tap water purifer as a last stage in the filtration process to ensure clean water and they always advertise that the resin is always rechargeable.
is at
Full Review