Potion of the Turtle Master

To make a Potion of The Turtle Master (slow. IV/res. III;0:20), you first need to make an awkward potion

after the awkward potion is finished put a turtle shell in the top slot and wait for the Potion of the Turtle Master to finish

For the sTurtle Master II effect (slow. IV/res. IV;0:20), put a piece of glowstone dust in the top slot and the Potion of the Turtle Master (0:20) in the bottom slot

For a longer lasting effect (slow. IV/ res III;0:40), put a piece of redstone in the top slot and the Turtle Master potion in the bottom slot

If you want to make a splash Potion out of it you simply put a piece of gunpowder in the top slot

And if the splash potion is not enough for you and you want to make a lingering potion from it, then you just put a bottle of dragon´s breath in the top slot and the splash potion in the bottom slot