What is the general consensus on using a UV sterilizer in planted aquarium ?

I heard that they would tend to oxidize iron, which I assume means convert iron to
a less available form. I found an significant effect in one tank that I maintain.
It has a 9W UV sterilizer plumbed in-line with a 130 GPH canister filter. The
relatively low flow rate assures plenty of exposure time for water flowing through
the UV. Using a Hagen iron test kit, the iron concentration becomes unmeasureable
within 1 day of turning on the UV. I normally dose with iron chelate sequestrene
once a week or so, which is adequate to maintain measureable levels of iron over
that period without the UV.

So, the question is this: Are the plants being deprived of iron by the action of
the UV ? A followup question might be if the same is happening to trace elements.

I might add that I normally use the UV only for a few hours during and after a
tank cleaning; vaccuuming gravel and wiping the inside glass. The logic being that
there is a variety of algae and junk stirred up, making it a prime time to take
advantage of the benefits of the UV.