Can I use this with a Nighthawk AC1900 modem/router

[patricials]

Hello,

My ISP advised to get a third party router to improve connection. I have the Nighthawk AC1900 but it has not improved anything. I previously used a AC1900 range extender which did not do much (with the ISP own-router). Can I use both together and should that improve speed and range? Thanks

[plemans]

Way more info needed. 

What actual models do you have? AC1900 is a speed and not a model number. 

What size is your home? 

What are the interior walls made of?

What gateway is it connected to?