By default the vanilla potion id limit is 32, many mods extend that to 128 as that is still possible without changing much of the code. This mod goes further and allows you to make the id limit as high as you want, by default it is increased to 4096 which should really be enough for everyone^^. Obviously if you increase it to something really high you are going to notice a slight increase in memory usage. Also Potion ID conflicts generally go by unnoticed because they are not logged like other conflicts. This mod changes it so that conflicts are logged to console (Or the debug log if you so desire).
After you install the mod and run minecraft the potion limit will automatically be increased to 4096, if you for whatever reason wanna change this default value there is a config file available for that. Conflicts will also be logged to console naming both potions and their ids.
When you install this mod all active potion effects are going to be kept, if you remove this mod all active potion effects are going to vanish.
Feel free to use this mod in any modpack