I have a Mansfield toilet in our spare bathroom I recently placed one of those chlorine hanging sanitizers. After I did so the toilet started running every 5-6 minutes. I thought I may have dislodged something with the flush valve so I replaced it with a Fluidmaster Universal type. After installation about every 2-3 minutes it runs for about 5 seconds. I figured the new valve was bad so I installed another one. Same thing. I consider myself above average handyman/diy guy, having built 2 new homes. This may be very simple but am I missing the obvious? Also I did remove the chlorine sanitizer before I put the second Fluidmaster on just in case the problem was related to it. Any suggestions are appreicated.