My phone is hogging WiFi. Help?

[WeAllLuvChicken]

When my phone is connected to the WiFi, everything runs smoothly. That is, until I open an app. This app can be YouTube, Facebook, google chrome, eBay, it doesn't matter. As soon as I open an app nobody else connected to the WiFi can use the WiFi smoothly. They get lag, and very slow internet. It will take them minutes to load a page on google, and Facebook will not work for them. I am using a Vodafone smart ultra 6. The most affected device (with slow internet when I am connected) is a Samsung S5 neo.
Sorry if this is in the wrong category, I wasn't sure what board to put this in.
Thanks for any help.

[BandOfBrothers · Accepted solution]

Hi @WeAllLuvChicken and may I Welcome you to the forum as a new member. 

What speeds do you recieve from your isp provider. 

I use Ookla Speedtest.net to check mine. 

You all could try Forgetting The Wifi Network in your phone settings and re hook up. 

And or try changing your Wifi Wireless Channel in your Router and or Refresh Your router. 

A good Wifi checker App to use from Ofcom is 

http://consumers.ofcom.org.uk/news/ofcom-launches-wifi-checker/

[PedroC1999]

Who is your broadband provider?

Which router do you have?