There is also a slider under all the sound settings, which allows you toggle up or down the special effects qualities in Splash. These are things like sunbeams, fish silhouettes, bubbles, the sheen on an aquapedia species etc.
By setting the slider to the far left (1) it will have the least amount of effects and if you have it to the far right (10) it will have the maximum amount of effects.
Having this set to the lower end will assist your device if it is struggling with the game.