Accessing C# scripts from other objects

I'm sure this is asked a lot, but I have looked around but nothing seems to help fix this. I have a script that is going to activate image effects on a camera when the camera goes below a certain y value. I have linked the camera GameObject through the script and that seems to work fine, however, when I tried to link the three image effects, I get errors for each one stating that "The type or namespace name could not be found"

Here is the script:

 using UnityEngine;
 using System.Collections;
 
 public class WaterEffect : MonoBehaviour {
 
     GameObject WaterTop;
     GameObject WaterBot;
 
     bool UnderWater;
     
     GameObject PlayerCamera;
 
     private Blur BlurEffect;
     private ColorCorrectionCurves ColCorEffect;
     private GlobalFog GloFogEffect;
 
     // Use this for initialization
     void Start () 
     {
         PlayerCamera = GameObject.Find("FirstPersonCharacter");
         BlurEffect = PlayerCamera.GetComponent<Blur>();
         ColCorEffect = PlayerCamera.GetComponent<ColorCorrectionCurves>();
         GloFogEffect = PlayerCamera.GetComponent<GlobalFog>();
     }
     
     // Update is called once per frame
     void Update () 
     {
         if(PlayerCamera.transform.position.y < gameObject.transform.position.y){
             UnderWater = true;
             BlurEffect.active = true;
             ColCorEffect.active = true;
             GloFogEffect.active = true;
         } else if(PlayerCamera.transform.position.y > gameObject.transform.position.y){
             UnderWater = false;
             BlurEffect.active = false;
             ColCorEffect.active = false;
             GloFogEffect.active = false;
         }
     }
 }