First off, I'm no plumber. I've got a question and I can't find an answer on the web so either it's a really good question or a really dumb question. Here's the deal. My wife wants a whole-house water filter (any tips on make/model I should look into would be appreciated). The problem is, we don't have a lot of room for one anywhere in the house (any creative ideas would be welcome). I see these units that have a series of canisters all in a row... and I'm thinking, what if I mounted them one-atop-the-other in order to reduce the required foot print? Is this a bad idea?