Gabrielle wrote:
The one spot I have tried to meddle in is lowering the pH. After a
month, with plants (alive but not thriving) & turtles but no fish, my pH
was high at 8.4, and my total alkalinity was high at about 250. I very
cautiously used pH Down and now the total alkalinity is about 120, which
my test kit says is ideal, but my pH is still about 8.4. What can I do
to lower pH without further lowering total alkalinity? Nitrate & nitrite
are both in the safe zones and the water has gone from very hard to
somewhere between hard & soft. The pond is about 1400 gallons with a
small waterfall and 8' stream emptying into the pond. I'm in the Sonoran
Desert in southwestern Arizona with temps 100+ most days and I have to
top off the pond about every other day to cover evaporation. I spent
last weekend erecting a shade cloth awning over the pond to help with
sunlight & heat issues.

So why mess with the pH? 8.4 isn't bad, especially for goldfish or koi. It's
not like you're probably planning on trying to breed tetras (or some other
acid-loving fish) in the pond.

If you're having to top off that often, just be sure to do some "real" water
changes (30% or so) every couple of weeks. Sounds like you have a lot of
dissolved minerals in your water, and there's no point in allowing them to
accumulate ad infinitum.