Hi all,

Have a problem now & hope to get some useful feedback and expert advice from
you guys out
there.

I have a two-month old concrete pond of approx 1500 gallons volume complete
with a 0.5 hp submersible pump, external filter, a biological filter & a
waterfall. To curb an initial pea soup problem, I have added an 18W UV
sterilizer run by a separately dedicated small pump and the water is now
crystal clear except that the walls & floor are carpeted with green & browbn
algae. However, I believe that the system has sort of settled as these days
I only have to monitor & change the filters as and when necessary.

I live in a tropical country and have no trees or shade overhanging the
pond, thus exposing it to about 6 to 8 hours of strong sunlight on an
average day. I have added quite a bit of aquatic plants and shrubs in &
around the pond and hopefully this could help improve the balance.

One problem that I face now is the emergence of numerous free-floating
clumps of green algae every afternoon (after strong sunlight) which I would
scoop out manually using a net on a long pole. It is very irritating but
strangely, if left alone these clumps of algae seem to disappear by
nightfall. Beats me. What are these actually ? Are they called algae scum
(read it somewhere) and how do they come about ? Are there anyone out there
who have experienced the same predicament & how did you deal with it ? The
filter of the UV filter gets clogged up very quickly too. Wonder if the
reason could be the size of the pump or something else.

Appreciate any feedback.

Thanks & regards,
Danny