On Mon, 14 Apr 2008 10:48:56 EDT, "Reel McKoi"
wrote:

What was it before it was "just right?" My GF and koi have thrived and
spawned in water from a PH of 7.6 to 8.2. Your 8.5 is a little high. Just
curious, why do you keep it so high?

The pH comes out of the tap at around 7, but the alkalinity is
approximately zero, so I have no buffering capacity unless I add some
buffer. I try to keep the alkalinity at around 100.

I'd prefer that the pH be a little lower than 8.5, by the time I've
gotten the water suitably buffered, the pH is up. I use the
commercial product "Buff it Up" for ponds. Dissolves nicely and
doesn't cloud the water, and keeps the alkalinity up for longer than
sodium bicarbonate. The pH stays nice and stable, varying hardly at
all from day to day, and even not varying much from AM to PM.

I do get a lot of string algae in the pond, which I take out as I can,
but it keeps on growing. I don't mind it as long as it doesn't get
too carried away. But I suspect that it pulls a lot of CO2 out of the
water during photosynthesis, which pulls the pH up by the end of the
day. I do make it a point to keep the submerged algae under control
so it doesn't drive the pH up too too high by the end of the day.

Joan