I bought a little tank you put in your toilet tank that was suppose to get rid of calcium but it did little, they might have something at the box store. Mean while take a coat hanger and bend it and take a mirrow and look under rim and clean out the holes, make sure your water level in tank is on the mark and make sure the 1/4″ tube is in 1″ overflow. Let me know, You might be able to get something on the net.
Art retired plbg