I have not looked closely at Spotify, but does it follow the YouTube pay model of the more streams there are on your song the less pay percentage you actually make?
I offer these articles to look over to understand what I am talking about
https://thetrichordist.com/2014/11/1...-means-to-you/
https://thetrichordist.com/2014/11/0...and-heres-why/
https://thetrichordist.com/2014/11/1...ly-16-revenue/
http://tapeop.com/blog/2014/02/19/wh...low-royalty-r/
Out of all the streaming sites I have looked into Bandcamp seems to be the only one where musicians can make any real income on their music. I know the articles above are several years old, but the information is still relevant today.