Toilet leaking into toilet bowl

[ngt]

Hey, new to plumbing, but my kids play travel sports and we're a single income family...so diy time. My toilet is running in the bowl. I hear it refill during the night. It stops sometimes and then will start a while later. Playing with it tonight and found that if I pull the rubber tube going from the float into the drain tube all the way up and out of the water in the tube, the water stops running into the bowl. Just replaced the flapper. Not sure if this was a giveaway to what the issue was or not, but hoping it was. Any help would be appreciated! Thank you!

 

[havasu]

If the hose goes into the water, you can create a siphon action which will pull water out of your tank. It is also fine to cut this hose to length, but a pic posted here will ensure we are talking about the same hose.

 

[ngt]

This hose. It's always been pushed all the way down the tube into the water. I pulled it up so it's above the water level in the tube and the water stopped running into the bowl.