nxt covers the water marks. after a few weeks then it will appear again. You can try Ultimate Compound (UC) to cure the water mark.
Water marks are oxidations/stains, in other words they are below surface contaminants and cannot be removed by just claying. Claying only removes the above surface stubborn dirts and smoothen the surface for easier surface prep, also helps the wax to bond evenly and strongly to your clear coat.

Using UQD for claying will bring up the shine better because your paint can absorbs its "Nutrients" better. Alternately you can try Gold Class diluted wash for claying or NXT is also fine.

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Added on March 10, 2011, 5:45 pmTCHTAX, probably about 30 to 40 mins for the wax to dry. U can do a finger test by running your clean and dry finger on the waxed area, if the finger trail line appears to be hazy, meaning that it is not dry yet, if it appears to be clear paint, then you are ready to buff it off. However, the wax polymers will take up to 10 - 12 hours to fully bond to your paint. so try prevent your paint to kena water within that period of time. =) hope this helps.

This post has been edited by moonballoon: Mar 10 2011, 05:45 PM

it will, but only a thin thin layer. not even 1/10 of a micron. typically, our clear coat is about 8 microns thick, sanding process itself will take off about 1 or 1.5 microns. so UC is still considered as clear coat safe.

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Added on March 10, 2011, 5:52 pmfrom what i know that UC also works as "MAGNET THEORY" that "attracts" the stains out chemically. im not even good with scientific terms, so i dont know the chemical term. =)

This post has been edited by moonballoon: Mar 10 2011, 05:52 PM