PlayerPrefs not saving slider value & audio

for some reason, my slider and audio resets back to 1 when I stop and play the game after I changed the value. Here is the code, I can't spot anything wrong with it:

 //sliderText.cs - created by Kyle 06 Jan 2015
 //Attach to option sliders
 
 using UnityEngine;
 using UnityEngine.UI;
 using System.Collections;
 
 
 public class sliderText : MonoBehaviour {
 
     public AudioSource music;
 
     public Slider Master;
     public Slider MusicSlider;
     public Slider Voice;
     public Slider SFX;
     public Slider MouseSpeed;
     public Slider FOV;
 
     public Text MasterTxt;
     public Text MusicTxt;
     public Text VoiceTxt;
     public Text SFXTxt;
     public Text MouseSpeedTxt;
     public Text FOVTxt;
 
 
 
 
     /*public Text Text;
     public Slider Slider;*/
 
     void Start(){
         audio.volume = PlayerPrefs.GetFloat("CurVol");
         MusicSlider.value = audio.volume;
         MusicTxt.text = "" + MusicSlider.value;
     }
 
     // Update is called once per frame
     void Update () {
         //Text.text = "" + Slider.value;
         MasterTxt.text = "" + Master.value;
         MusicTxt.text = "" + MusicSlider.value;
         VoiceTxt.text = "" + Voice.value;
         SFXTxt.text = "" + SFX.value;
         MouseSpeedTxt.text = "" + MouseSpeed.value;
         FOVTxt.text = "" + FOV.value;
     }
 
 
     public void VolumeControl(float volumeControl){
         audio.volume = volumeControl;
         PlayerPrefs.SetFloat("CurVol", audio.volume);
     }
 }