Should I enable eCPM floor in manual mode?

Question

Google AdMob

Hello,
I'm just starting to understand the intricacies of AdMob, so please don't hit me hard with slippers.
Advertising - banners, interstitial and rewards. now on the day of ad impressions in general 15k somewhere. Income in the region of $ 15-16 per day. Are these normal readings? The eCPM floor indicator is off now, should it be turned on and configured manually? Will it improve income? If so, how are prices determined?
Thanks in advance for your replies.