Well, I've spent an hour digging around for my receipt and I can't find it. Neither can I find the instructions for building the tent which, by the way were terrible to say the least. But to give you an idea this tent was purchased in late 2008. I have yet to grow anything successfully as of yet. This set of clones is my third attempt at growing. I would assume however that these are newer tents, but who knows at this point. Here is the info I got off the net about the brita filters...

What do Brita® Faucet Filtration Systems remove from tap water?
Brita® Faucet Filtration Systems with Advanced Features (Model FF-100) and Brita® Faucet Filtration System (Model OPFF-100)
The Brita® Faucet Filter removes microbiological cryptosporidium and giardia. It also reduces lead, TTHM, VOCs, lindane (pesticide), 2,4-D, alachlor, atrazine (herbicide), chlorine (taste and odor) and sediment1. For more information about the impurities that Brita® Faucet Filters reduce, including any health risks they may help avoid confusion.

Also...

How the Brita® Faucet Filter works
An added layer around the filter traps large particulate matter from the water
Activated powdered carbon acts like a sponge, sucking up Chlorine (taste and odor and Benzene)
A zeolite acts like a magnet attracting Lead

I am still not educated enough to know if any of that listed is a problem or not.

Now onto the water thing you mentioned. If after reading this you think its better for me to just go ahead and use tap then I'm all over it but, you say that RO water or distilled water using CalMag is my best option. First, considering I'm using a 40g resv. I really want to get my water from the house. I don't know much about plumbing so I don't know how hard installing an RO filter will be in addition the cost of one of them. If I did get an RO filter is there any way I can make it where its not "inline" with the rest of my plumbing? Like something I could attach to a faucet or something easy like that? Also, how would I go about distilling water? Would it be too much of a hassle considering its a 40g resv. and I drain/refill it every two weeks? I've never checked my grow store for CalMag because I didn't know anything about it till I visited this site...do you think most grow stores will carry it? Also, if I were to use just plain tap if you think its better than using a brita filter, should I still use CalMag or do you only use it for RO and distilled water? My water treatment plant said average is 120PPM, after reading some other posts that doesn't seem all that bad to me, and if thats the case is it low enouph where I should use CalMag?