i'm curious, what is the difference between water condition and water clairifier?
what are their intended uses?
the only one you will need is the one for dechlorinating water.
personally, i'd go pick up a master test kit. it comes with several different tests that will be useful in the future to diagnose problems. you will get more complete answers for your questions if you can provide some basic chemical information about your water.
the tests i'd recommend for sure are for:
ammonia
pH (sometimes both a high- and low- range are needed)
nitrAte (not nitrite)
my master kit did not come with a nitrate kit, but did include tests for KH, GH, and nitrIte in addition to both pH tests and an ammonia test. if i remember right, theyre about 20 bucks at most chain pet shops.
knowing the various aspects of your tap water's chemistry, even in layman's terms, will extend your interest and success immeasurably.