made changes in tanks controller

src/controllers/tanksController.js

@@ -140,7 +140,7 @@ exports.getTank = async (req, reply) => {
  //   throw boom.boomify(err);
  // }
 //};
-let intervalTimer;
+
 exports.updateTanklevels = async (req, reply) => {
   try {
   const customerId = req.params.customerId;
@@ -154,7 +154,7 @@ exports.updateTanklevels = async (req, reply) => {
    
     
     //console.log(Number)
-    intervalTimer=setInterval(async function () {
+    setInterval(async function () {
       
      // const randomNumber = Math.floor(Math.random() * capacity)
       //const randomNumber = Math.floor(Math.random() * (5500 - 1000) + 1000);