Joel,
The value of a PUR filter on your water it depends upon your source water, I'm assuming your tap water comes from either a well or sodium softened apartment/city water? City water is bad due to all the crud the cities put in it (flouride, edta, etc...) and then it's usually run through a sodium softener (the culligan type machine they use those big yellow bags of salt pellets in). Sodium will collect on your plants roots and it will crystalize and dehydrate the plant (most any CPs) no matter how much water you pour on it. Well water is generally pretty hard (unless you're from TN, I believe their well water is very soft) and has a lot of minerals which VFT and other CPs are not usually accustomed to in nature. And it can shock the roots to be continually watered with that kinda water.
The actions of a PUR filter will simply remove chlorine, flouride and other nasties the city adds to it because the PUR filter is simply a tube of aquarium grade activated carbon. I would save up and get a starter Reverse Osmosis unit for under the sink. This will remove about 90-98% of all chemicals and minerals coming from your sink. Cheapies good enough for plants sell for like $75- $100 but you can spend up to $500 depending upon what you want to remove. Try going to
http://www.marinedepot.com and look under their RO unit section, it shows a lot of models and explains some of what it removes.
Good luck!