USA travel

If I go to the US & leave after 6 months, how long do I have to stay in Canada b4 Ican go back to the US. Am a canadian citizen?

thanks

Depends on how strong your ties in canada are, you could return next day, or be refused for six months.

So, is there a set time you have to b out of the US to legally re-enter, Like Costa Rica, after 3 months you can leave for 72 hrs and then legally re-enter....

No there is no "time" factor. Each entry is judged on your ties in canada. You can be refused forever if you do not have sufficient ties.