I've got a uv as well, but for the most part "and I am no expert here for
sure", the uv seems to control the pea soup water a lot better than string
algae. I guess it's because the stringy stuff doesn't actually go thru the
filter. I believe it has alot to do with the winter mulm and debree that
gathers at the bottom and on the sides of the pond. Guessing here a little
bit, but it seems to me, I get a small ammonia spike as soon as spring kicks
in from this decaying stuff and the uv controls the soup but can't control
the string algae so it blossoms and then my regular plants, lillies and
marginals start growing and everything just cleared up. What makes me mad
is I give it a real good fall cleaning and still get this winter mulm, not
sure where it comes from, but it's always there in the spring,
dang'it....lots a luck