Another ponder confesses ...

First confession: It's been about a year since I last tested our pond
for anything ... yep, did it once or twice last year with the pool test
kit to check ph and alkalinity. This year I ordered a Tetra pond test
kit from http://www.koivillage.com -- it has tests for ph (salt and
freshwater), nitrite, ammonia, GH and KH. And today I tested the pond water:

pH: 9.5
NO2: 0.3
ammonia: 0
GH: 1.5 dH
KH: 2 dH
CO2: 0,1 (based on a chart analyzing pH and KH)

So, if I'm reading and calculating everything correctly, I have highly
alkaline and soft water. I also have green algae water (2d confession).
Now if I add potash will the pond plants be better able to use the
nutrients in the water which will reduce the algae? Or do I want to add
gypsum, lime, baking soda, or epsom salts? Or a combination of the above?
--
Kathy B, zookeeper
3500gal pond, 13 pond piggies
Oregon, Zone 6