Excellent experimentation. 4.2 x 117 => maybe 400 watts? Does your meter show true power, or just volt-amperes? Does it show power factor?

Anyhow, 0.4kw x 24 x 30 = 288 kwh/month. At $0.14/kwh that's $40/month. I think that's more than most folks realize.

By the way, you may be able to measure the actual flow gpm to within 10% with a 5 gallon bucket, a heavy duty garbage bag, a household scale, and the timer on your phone. It depends on whether you can reliably seal the throat of the bag, so that the pool inflow is capture by the bag. You'd also need a decent twist tie (or a nylon wire strap) to seal the bag . . . and the bucket so you can lift the bag without busting it.