OK. You've got several options here.

1. We can get the water in shape to OPERATE, with no new scale, pretty easily. But, with that high calcium level, it's going to be hard to get it into a calcium-removing state. If want to just operate the pool, and let the scale go, you can lower the pH and aerate, till your TA is much lower, and you'll be fine.

2. To LOWER the calcium, you have two options. The first is simply to drain and refill. But, with a fiberglass pool, if there's ANY water in the ground, your pool can FLOAT out of the ground, destroying it. If you're on hillside, and the weather hasn't been soggy, you are probably fine. If you are in a flat or low area . . . be VERY careful! (Since you're in Las Vegas . . . it may not be an issue!)

3. Your second option is more complicated, but won't waste so much water. You can do a 'lime-softening' process, by adding a bunch of sodium carbonate, till the calcium precipitates, and then vacuum and filter it out. Doing this, you can end up with quite low calcium -- lower than the fill water -- and that will help you strip the scale. Here's the process:

+ raise your water level to the max -- if it's safe, raise it to spill over.
+ remove your cartridge from your filter
+ add a dose of PAC floccing agent
+ follow it with sodium carbonate till your pH > 10.0
+ mix, turn your pump off, and let it settle.
+ vacuum the floc to waste. (you may have to add T valve to enable this)
+ replace the cartridge filter, turn the pump back on
+ add muriatic acid till your pH is ~ 7.0, and begin aerating
+ use acid + aeration to strip carbonate alkalinity till your TA > 80 ppm
+ hold your pH at 7.0 - 7.2 till the scale is gone; try to keep the water level ABOVE the scale.

The last option is by far your best choice for removing scale and stains. And, it's not as much work as it sounds, but you will have to be careful to follow the process. To do it, you'll need several items;

+ Poly aluminum chloride floc
+ Wide range pH test strips
+ Washing soda from Walmart (yellow box, maybe 8 boxes?)
+ Muriatic acid from Lowes (gallons, maybe 4 gallons)
+ HEDP for post treatment

You can get the washing soda (soda ash, pH up) and muriatic acid locally and cheaply; I'll need to help you get the exact item on the other three products, if you're interested.

Given your fill water's condition, and the high evaporative rates, learning to do this might be worthwhile. You *should* be able to get lower calcium and alkalinity levels than you have in your fill water. I'm guessing you might need to do it every other year, to avoid scale, and I'm guessing water in Las Vegas costs enough so that this should be cheaper than draining and refilling. (I'm guessing total cost may be around ~$100.)