i bought a ti-10 with a bg80 strung at 22 lbs. however now the string tension is about at 17 and feels really slow and sluggish. can you guys advice me what string to use at what tension to get the optimal power out of my ti-10. my skill level is intermediate. i play in high school varsity. with the current string, i can control my racquet pretty well but i have problems with power.