Use Corrosive Heat for general use: Corrosive has 50% bonus against grineer and heat has 50% bonus infested.
Use Viral Electric for corrupted and murmur: viral has 50% bonus against corrupted, electric has 50% bonus against murmur
Use Magnetic Tox/heat for corpus

Secondary Enervate essentially boosts critical chance by an average of flat 80%, meaning you will see yellow and orange crits.