QUESTION:
My question is since Mars has two moons does that mean that the tides 
would be three hours instead of six hours?  
 
ANSWER from Bruce Jakosky on May 21, 1997:
The two Mars moons, Phobos and Deimos, orbit Mars nearly in the plane of
its equator.  Phobos goes around once every 7.7 hours, and Deimos every
30.2 hours.  As a result, you would think that Phobos would raise a high and
a low tide twice every 7.7 hours, and Deimos twice every 30.2 hours--each
would raise two high and two low tides each time it orbits.  However, the
raising and lowering of the tides results from the movement of the satellite
RELATIVE to the surface.  And, since Mars itself rotates on its axis
once every 24.6 hours, the movement becomes much more complicated.  As
seen by a person standing on the equator, Phobos would go around once
every 11.2 hours (in other words, by the time Phobos went around once,
Mars would have rotated a little bit and Phobos would need to go further
to catch up with the person on the surface).  Deimos, because it goes
around in a period longer than 24.6 hours, would appear to a person on the
surface to go around in the opposite direction, once every 4.4 days.

As you can see, the tides would become quite complicated.  Of course, Phobos
and Deimos are both very small and they do not have very much mass.  As a
result, the tides that they raise would be very small and extremely difficult
to detect.  And, there are no oceans on Mars to show the effects of the tides
easily; the tides do show up in movement of the solid rock of the planet
(as they do on the Earth), but that movement is much smaller than the
movement if water were present.