Hey Larry.
Two things come to mind
1. Did you thoroughly clean out the ammonia-soap residue before adding the new cleaner ? Thinking the ammonia may have “boosted” the heat index due to chemical reaction.
2. Is there are recommended temp for this solution ? Many times I’ve seen where they state that you should not heat them, as it can actually reduce the efficiency.
Here’s a link from Zenith that may help ?
Temperature Effects
Best regards,
Randy