I know them well, great company, why would anyone here care where you buy it from? Unless you were going to buy absolute junk from the big box stores, or scam equipment, most people here dont care.
I agree with Gary, the right way to do it is with a backwashing carbon tank, but if your budget is tight, and Aquatel puts in the right DLFC button (4-5 GPM depending on water temp), you will be very happy with the media guard. Even up to 10 GPM, we see a 90+% reduction in chlorine with a KDF55 media guard, and they last for 3+ years. You simply replace them every 3 years, and you are good to go. Replacement is fairly simple and fairly inexpensive. Plus you get the added benefits of heavy metals removal.