What gives more Graftblood from Breach Hive?

I asked in global and some one said that you need to turn the purple dots (spawn rifts?) into pink dots by running near them in order to get more Graftblood from the encounter. The wiki says destroying walls will spawn more rifts creating more monsters resulting in more rewards. Does anyone know exactly what results in the most Graftblood? Does the number of monsters killed during the encounter matter?