For Years, RedLine's Watter Wetter was the industry standard for coolant system additives. Motul has changed the game with their entry to this market with their "MoCool".
Use it just like you have used Watter Wetter, by mixing with distilled water. When mixed with water 20:1, it reduces temperature by 15c ( 30 F ). This can be the difference between "ok" and "not ok" on a hot day at the track, where running temperatures tend to be slightly higher than normal.