Plain water or salt water?

Do you have an easier time retaining plain water or salt water? If salty, is it easier to retain slightly salty or highly salty water?

I have tried both salt and baking soda. Both make retaining the enema much more essy. But in my case I find it makes releasing the enema very difficult. As long as I'm not overly gassy, I can usually retain 3 to 3 quarts easily as long as I lay on my back. J&J or Ivory are the easiest for a quick and complete void. Which I prefer.

For small enemas, tap water alone is perfectly fine.

For larger enemas, from 1 liter upwards, 1 teaspoon of salt should be added per liter of tap water.