My money is on a leaking toilet but the “always 2:30” is puzzling.

yep...that is what is stumping me. Like I said I had a leaky toilet in the other bath...but you could hear that at random times all day.

One way to tell if it is a leaky toilet would be to turn off the water to the toilet right before you go to bed, then check the holding tank in the morning. If it is low, there's your culprit. I'd try that before spending the time and money to replace any of the parts.

Just my $.02 worth.......

Try turning off the supply line for a night to see if that is the issue.

Good idea. Will do that.

Do you have a water softener & filtration system? It could be the self purging/cleansing of your system.

Wasn't there a movie about something happening everyday at 2.30 am sharp? Can't remember the name to save my life.

mystery solved. It was the flapper.I marked water level and sure enough it was dropping slowly. replaced...wait and see...

Same problem.
 

Thanks for the top. Same problem solved.

Your welcome. My level seems to be holding after five hours..so I guess I saved a plumbers bill.

Thank you for providing the solution to your problem, I know other readers appreciate the feedback.

We certainly do. I surmised completely incorrectly.

Before you spend any money on parts, check to see if the float is allowing the water level get too high and run into the over flow. Sometimes this happens when the float is out of adjustment or when the float system needs cleaning. This could cause the float to periodically open the fill valve. If the water level is right up to the edge of the overflow tube, that is probably the issue.

The problem appears solved with flapper as it didn't make noise last night. Although water level is right up to fill tube. How do you adjust float?

I learn something everyday on TOTV. Thanks for today's tidbit.