Alkalinity way high

[nitjt]

I set up a new Ca reactor I can't figure why my dKh is so high I started by checking the effulent and can't get a number its so high and then checked the tank and it over 25. My pH is running around 8.13, Ca is 420. I use a Salifert test kit everyting in the tank looks fine no problems the tank has been running for about 4 years and I added the reactor about two weeks ago. I don't know what to do if anything to lower it. Please help thanks.