My kh is low?

Question

i have a 130 litre freshwater tropical community tank and all my water reading are perfect except my kh. its at 4 drops and it should be at 7. one of my swordtail mollies died today. my tanks not overstocked and i take out 20 litres weekly with a gravel vacume. does anyone know why? is it hurting the fish?

thanks

Answer 1

Drops?  Drops aren't a measure of KH...  There is either dKH (degrees of carbonate hardness) or ppm (parts per million).  If you want to slowly raise your pH, try adding a small amount of crushed coral, limestone, concrete, shells, dolomite, or similar calcium carbonate based substances.  Another choice would be to start adding small amounts of Rift Lake Cichlid salt, as this is high in calcium carbonate.

Answer 2

I know it's redundant, but just in case it's not:

Have you been keeping a very close eye on your pH?

A kH fall on it's own won't hurt the fish (kH is a buffer for the pH, not something that directly affects the fish), but it may change the pH, which could.