Sent same notification only each 3O min

I’d use a different name for each blind time you need.
Otherwise timers can get restart eachother.
You could use blind_flowname for instance, and when you need multiple blind timers on one canvas, you could use blindA_flowname, blindB_flowname and so on.

You can create new timers right after inserting a timer card, and use unique names, by entering a timername in the “pick” field.
If the name is unique, it presents a dropdown marked with “new”.
Important: after you entered the unique name, you should select it to actually create a new timer.
When you save the flow, the timername will be shown as existing timer:
The same “pick” field also shows existing timernames you can select in new timer related cards, like “When timer x has finished”.

Chronograph has a nice dashboard, where you can view all running timers, and also pause/resume / stop them as well.
It also shows the last run time of timers

(With the word timers i mean timers, stopwatches or transitions)