i got mine from ebay. it works well. the trick is to make sure that it takes the standard catridges that you can get from bunnings or your local fish shop. I would also recommend only going 3 or 4 stage. 5 stage will be way too pure and you will have to add stuff back into the water. I have a 4 stage on adelaide tapwater, known through-out the world as horrid (serriously, international ships will not refil their freshwater tanks here :O), and i have to mix some tap water back through to bring it up to suitable.
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