The right tension is no tension. Chain drive systems require some slack in the return loop. The ideal adjustment allows minimal slack at all times.
Because there's some eccentricity in the sprockets the amount of slack will vary, and you need to allow for that. A general rule of thumb is 1/4" vertical free play at the center of the lower loop. Then rotate through a few pedal revolutions to confirm that there are no tight spots.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.