Whenever the arcanist successfully uses the counterspell exploit, she regains a number of points to her arcane reservoir, which is determined by the level of the spell countered. Spells of 2nd level or lower do not restore any points to her arcane reservoir. Spells of 3rd and higher restore 1 point to her arcane reservoir for every three spell levels (rounded down), to a maximum of 3 points at 9th level. The arcanist must have the counterspell exploit to select this exploit.
Pathfinder Roleplaying Game: Advanced Class Guide © 2014, Paizo Inc.; Authors: Dennis Baker, Ross Byers, Jesse Benner, Savannah Broadway, Jason Bulmahn, Jim Groves, Tim Hitchcock, Tracy Hurley, Jonathan H. Keith, Will McCardell, Dale C. McCoy, Jr., Tom Phillips, Stephen Radney-MacFarland, Thomas M. Reid, Sean K Reynolds, Tork Shaw, Owen K.C. Stephens, and Russ Taylor.