Apex chart showing power today but has a 'Tail'

Configuration Frontend
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1

I want to show power usage today so set up the following code:

type: custom:apexcharts-card
header:
  show: true
  title: Household Power Consumption Today (kW)
  show_states: false
  colorize_states: true
series:
  - entity: sensor.electricity_meter_power
    stroke_width: 2
graph_span: 24h
span:
  start: day

However, it displays with a horizontal tail from now to midnight tonight at whatever is the most recent power level. It looks ugly.

image
image724×484 21.5 KB

How can I rid of it?

2 
series:
  - entity: sensor.electricity_meter_power
    stroke_width: 2
    extend_to: now
3

Thank you.