IMO3 is considered Propagated IMO (PIMO) where the microbes you collected in your Seed IMO (IMO 1&2) are grown to immense populations. IMO4 is considered Activated IMO (AIMO) where the PIMO is mixed in equal proportion by volume to field soil and/or red clay dirt.
Both in PIMO and AIMO the liquid solutions are added to ensure nutrient content and "food" for the microbes to populate. The piles should be brought to ~60% moisture content once, then allowed to ferment until they cool, turning frequently so the temperature never exceeds 120F or 50C.
When combined in equal volumes of PIMO with field soil, the result should heat up within the day. If it does not, there may be the issue of contamination of the field soil, the proportions of PIMO to field soil may not be correct, the PIMO was made incorrectly, or the moisture content is incorrect.
