Are you sure it's 40K, or is that the volume at overflow?

I ran the calcs for typical dimensions, and it came out to ~32K, or maybe less. What is the actual water depth in the shallow part of the L? Which is the deep length -- 36' or 41'? What's the actual water depth in the hopper (deepest part)?

OK, other issues.

1. Make / model of the filter? (Pump may be too big for filter.)
2. Make / model of the pump OR amps and SF (Service Factor) of motor?

Meanwhile, chlorinate your pool with 1 - 2 gallons of plain store-brand 8% household bleach added each EVENING. Hold off on the cal hypo you have -- your calcium and alkalinity levels may be high. Wait for the the kit.

If you have a top mount filter, pop the top, and check the sand level.

Take pictures of the pump, filter, and piping, and post them using Picasa, Flickr, or Photobucket links, or by emailing them to poolforum@gmail.com.