Need help on spa volume

[jurmanji]

I'm terrible at math so I hope someone can help me. I know my estimate must be off because my pool math never works.

I have a spa with spillover basin.

Basin is 41x33x18

Spa is 78x96

stairs are 18 width
19 depth

At the deepest point the spa is 44 inches

I had estimated 1200 gallons

Help!!!!

 

[JVTrain]

Just using the formula for an ellipse in two sections:
41x33x18"
78x96x26" (the 26 is 44 depth minus basin depth of 18)

Gives about 665 gallons.

If it is rectangular, it's closer to 950 gallons.

Do the stairs protrude from the side? What is the distance from the back of the top step to the front of the bottom step? If they protrude outside the other dimensions, you're likely not adding much more than 20-40 gallons there, depending on length of steps run.

 

[philboyj]

My calculation was close to 1100 gallons using 7.5 as multiplication factor