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

"Marcus Tait" wrote in message
...
To increase just the KH you can add sodium bicarbonate (baking soda). To
increase KH and GH in equal amounts you can add calcium carbonate. calcium
carbonate is probably best because your plants will need calcium which you
will be short of in sof****er. Also you can add magnesium sulphate (epson
salts) which will increase just the GH.

For my planted tank a aim for a KH of about 5dH and a GH of about 6dH. the
calcium carbonate i add takes both GH and KH to 5dH and the magnesium
sulphate i add then takes GH to 6dH. With CO2 injection at about 25ppm it
gives me an pH of about 6.8

Be careful when adding anything which changes your KH as it will change
your
pH as well. Add it slowly.