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Your numbers...

KH 53.7 to 71.6
GH 71.6 to 107.4
pH 8.2 to 6.8/7.0

These seem like fairly large swings in water chemistry. What about ammonia?
Do you have any ammonia readings? How about Oxegynation? Are the fish
looking for air up top? I am wondering if these swings in chemistry could be
aggrevating some other condition like an ammonia spike or lack of
oxygenation.

BV.


Hi, Thanks for writing back. The ammonia and nitrite have been
consistently testing negative. I haven't seen any fish looking for
air up top, and we have an air bubbler and a waterfall in the pond, so
I think the oxygenation should be okay. I don't know how to measure
it, though. I did notice that, yesterday, there weren't quite as many
air bubbles coming up from the air pump as there should be, so I
cleaned the air pump and it improved. It's been a big spring for
string algae. Hmmm, I wonder if that could be related to anything?

Joan