Kh is carbonate hardness. That is how well buffered the water is to protect from ph drops. It has nothing to do with hardness unless the main source of carbonates are calcium. Then you would expect
gh to go hand in hand with
kh but this is not always true.
Gh is usually what is referred to when describing hardness. At 57ppm you are only slightly hard according to water hardness charts.
I went down to London on a training course and made a cup of tea using the training rooms kettle. I opened it up and to my horror the element had a think lime fur on it. Made me realise how much harder water is in the south compared with the north.
As for the rams, I wouldn't worry too much.
Sent from my iPhone using Aquarium Advice