"alex crouvier" wrote in message
...
If you have sof****er (gH, kH 3) and employ DIY CO2 at 15ppm,
what do yo do to increase gH and kH? pH is at 6.8

Regarding GH, it's more important to know the individual levels of Ca and Mg
then the combined GH. If you have a sufficient ratio of Ca and Mg, then a GH
of 3 is fine. But if almost all the GH is made up of Ca, then you should add
some MgSO4. Contact your water utility to find out these mineral levels.
__
Alex