"linda mar" wrote in message
...
Is there a way to increase KH without increasing pH? or do they always go
hand-in-hand?

I have soft water (tap seems to vary between GH/KH=2 and GH/KH=3), but
they
add something in the water to make the pH very high (fresh out of tap is
close to 8.0). so when I do water change, it keeps my tank quite alkaline
(somewhere in the 7.5 region). I would like to increase KH one or two
degrees, but really do not want the water to be more alkaline than it
already is.

linda

Many water systems add some sort of hydroxide (alkaline) to reduce
corrosion. Mine adds sodium hydroxide. The tap is 8.9+ but drops rapidly
once out of the tap. Aging the water generally will help.

As for adjusting kH without affecting pH, the answer is no. Up the kH the
pH goes up, unless you add CO2 to balance the pH. You can also use an
acid buffer to drop the pH while raising the kH.

Out of curiosity, does your pH tend to drop consistently between water
changes? In my Pre-CO2 tanks the kH and pH would slowly drift down over
time, actually it still does.

Bob