Cooling System Flush Cleaning Solution Recommendation - John Deere 6400

[landrand]

I'm getting ready to flush and clean the cooling system on my John Deere 6400 tractor. The operations manual states that I should drain the system and fill with a "commercial cooling system cleaning solution". Run until hot, then drain cleaning solution. Any recommendations on what product I would use as the "commercial cooling system cleaning solution"? I'm going to use distilled water after the cleaner then then drain it. Then I'll fill with the John Deere Cool Guard coolant.