I recently got some tonina fluviatilis, and thus need soft water. Now the question is how do i make it soft? First, forgive me that i have weak understanding of GH and KH and am trying to see if there was any previous discussion. so can someone explain in some layman's term? If the water is soft, does it affect other plants? the nerites in my aquarium has really sad looking shells so i added a small amount of calcium carbonate 2 days ago without knowing that it will make the water harder. so i guess i'll have to make a massive water change later today... any other substance that will make the water hard?