I assume that you are indeed talking about a redwood, rather than
fiberglass, tub. If so, be aware that is critical to keep the water
chemistry within the specified range. This is particularly true with
chlorine. If the chlorine in a wood tub goes too high, it destroys the
cell structure of the wood in contact with the water. The wood surface
then gets a "fuzz" on it that is very difficult to remove.

You cannot do a chlorine shock treatment on a wood tub for this
reason.

I owned a redwood tub when I lived in San Diego in the early 1980s and
will never own one again.