Chai98a,

If you have enough RAM, it is easier to keep the seconds, minutes, hours, etc., all in their own variable. This saves building and unbuilding combined variables each time a second passes. I have posted two examples of clocks here

http://www.picbasic.co.uk/forum/showthread.php?t=2129

that uses separate variables for each “item”. The code sections of interest for you are at the very end of the programs. The first only has minutes and hours but seconds could easily be added. The second has all three. Check them out and see if they might help.