mg/l is the same as ppm for our purposes. You can divide this by 17 to get to degrees. Your KH is around 1 degree. If this is "normal" water it is likely your GH is also around 1 degree. Did you measure the GH as well?
You should try to add a measured amount calcium carbonate to a gallon of water to bring it up to a GH of 4 or so. This will also increase your KH a similar amount. Once you determine how much to add to a gallon multiply by the number of gallons in your tank and slowly add that amount over several days time to bring up your GH and KH in the tank. Remember to add the same proportion (not amount) to your water change water.