Potion Storage Mod adds a button that simply puts your active potion effects on hold. It is in the upper left of the screen. Clicking this takes any active potions you have and pauses them (saved to your player NBT data) for later. Click again to reapply. This is great for survival for when you eat a gold apple, or say you drink an 8 minute speed potion. But then, you are done using the speed effect with 3 minutes left, and it goes to waste while you stand around crafting or fighting. Well, now you can pause that timer and turn it back on later. In other words: If you click the button while ANY potion effects are in storage, it always gives them back to you. So, if you put some in storage and drink more, then pushing the button will put more in storage.