I’m sure it’s on the forum somewhere, but I’ve never seen it. But right before you fill your pool, you can take a photo of your water meter. Immediately after it is full, take another photo. Using both photos, you can calculate how many gallons your pool / spa are. I’ve done it to both of my pools. You can usually find how to do the calculations on your water companies website or YouTube. I found a calculator to convert the cubic meters (which is how my water meter displayed usage) into gallons after a quick internet search. I’ve done this for both of the pools I’ve owned. I turned my irrigation off and told family to shower before I started filling so the calculation would be more accurate. So yeah, that’s pretty much all I’ve got. The end.