Newbie and frustrated

OK....

Live in San Diego. Had a pond installed last September. About a 3
foot rise waterfall into a pond of about 800-1000 gallons. Installed
by local contractor. Gave us Koi (6) and some water lillies plus
"Aquascape Designs String Algea Buster (SAB)" and "Aquascape Design
Aquaclear"

Followed all directions rigorously in respect to bacteria, cleaning,
etc. But as you may have heard, southern california had more rain than
we have had in the last 100 years. So a fair amount of run off into
the pond and outright rain. Had to pump out water on numerous
occasions and other times simply let it overflow in to landscape.

With warmer weather planted some more lilles and some marginals.
Lillies going well. I have about 10-15% surface area covered and more
pads every day. I do not have any "bottom plants" but strongly
considering adding them.

HOWEVER, I have a serious string and single cell (green water) algae
problem that is driving me to frustration.

Been spiking (triple the dose every day) my pond with both "clear"
bacteria and SAB. Hand cleaning out every day the string algae that is
easy to get out and actually pulling some off from individual rocks.

But not sure it is helping! Or at least I can not noticeably see a
difference. Is my only hope to drain the pond and start over? Should
I have patience with the product I am using? Should I try something
different (there seem to be a huge number of different concoctions out
there - any objective reviews?)