Got it. I received water hardness kit today. I will try to test water tonight. The kit is “Hach” I hope it’ll tell me more.
I’m using softener for both cold and hot. My water heater though is about 30 years old. I know… don’t laugh.
May be I should run hot water again to empty the tank.
I’ll let you know what is result of test as soon as I’ll do it. And Monday or Tuesday I’m going to check my resin. Hopefully it’s all there :-/