I believed the pools are were suppose to be capped at 10 stacks. Each pool adds 10% of your experience needed to level at that particular level so your max pool (10 stacks) should be your experience needed at that level. As you can see here I have 9b pool, way higher than 10 stacks. Not sure if this was a change in the latest patch or something else.
Pools of Reflection Not Capped at 10 Stacks?