Hmmmm, I've noticed my baitcasters seem to have less casting distance lately and have been newly spooled. My question is if you spool the line under too much tension, does that take away casting distance? If you spool too loosely, does that make you more prone to backlash?

No and yes. I personally don't believe you can put too much tension on the line when spooling. If you did, it'd break. Unless it's digging into itself, it would only affect casting distance on your first cast. After that, it'd be under normal tension. Too loose and you're asking for trouble.

Not to change the subject, but how the line was spooled, tension wise, may not be what's robbing you of casting distance. When was the last time you cleaned the spool bearings and shaft? Do you back of on the spool tension after you're done using the reel? Did you go to heavier lb. test line than you had on the reel previously?

All these and more could contribute to less than optimum casting distance, or in your case reduced casting distance.

Agree 100% with the above. Only problem I ran into with spooling line was either using too much or too little. There should be 1/16-1/8" of spool left after you spool up. Too much and the line can come off to fast. Too little and it affects distance.

I cleaned the bearings and shafts, and put a drop of oil on the bearings. Maybe it will be better tomorrow with the new line I spooled on.