There are some people with conditions which make it necessary. However, unless you have some special medical condition, if you have a little chlorine in the water, I think it is your friend, not your enemy. I think that the number one problem with water systems is usually the result of "goo of life" smell (i.e. usually sulfur dioxide like, rotten egg smell).
I don't think a carbon filter would really block or materially affect a Whale foot-pump. The first thing that you should have is a -- do you have one of those little, inexpensive "screen" filters for gross particulates. Then you can put a hardware store, household filter body in line. (That seems to me like overkill, but different folks, different strokes.) Then you can go with various degrees and types of filters that range up to carbon blocks.
We've sailed and been based in the Chesapeake for a lot of years on three boats. The only carbon filter is on the freshwater flush feature of our J/Boat's RO watermaker. That filter body is their simply to protect its membrane which would be damaged by chlorine. Our prior Pearson 35 and Sabre 42 boats had none of that. If you have a "clean" (reasonably purified) tank and lines, just using municipal water which is cycled through the system every two weeks or so seems to be fine. Peggy's book and posts on boat plumbing systems (as well as, a simple web search) will give you guidelines for purification of you on board system.
The filter will "mask" the underlying issues in the tank. You should occasionally purify your tank anyway, even if you have a carbon block filter. Let your nose and taste be the guide.
Also, if you have a carbon block filter -- you will be needing to deal with that as part of your winterizing process. You'll need to either take it off-line, drain and dry it over the winter; or, you'll have to change it every year (which it really won't need, with your actual water use); or, you'll have to deal with the result of it being soaked in potable antifreeze. The potable anti-freeze's flushing will take you a LOT of water and futzing around :^))). In that case, you'll probably want to make sure you pull the filter, dry it out, flush the system without the filter in the Spring, and then reinsert. I know this because of a friend who put one in on their pressurized boat, and then was griping about it. :^)))))