Is it me or is balance the only school that doesn't have any protection skills against its' spells? I think that is totally unfair. If other schools spells can be protected against, balance spells should be the same.
If balance had shielding against its spells, then there would have to be a balance prism as well. To create that then, what would a prism be? My thoughts on that are a prism that would automatically sense the school of the opposing "monster/opponent" and automatically switch to the counter school. Fire to Ice , Storm to Myth and so on. So you see, a shield for balance would mean a whole lot more than just having a shield. As posted above by Ergos, you can, through your clothing and accessories, build a resistance to balance which is easier than restructuring the entire school frame. Balance after all is just that, a balance between the schools. Elemental in nature but balanced between all.
Ice school has a shield that takes 50% from any school spell including balance so if you want it make sure you use ice as a secondary school or there is also a necklace called tower shield that will give you one usage of it per battle.