phappy:
2-3ppm is the "site average" so to speak. Some pools 1ppm/day others 4ppm/day. Lots and lots in the 2-3 range. Sun degrades some and some gets used to break down organics that blow in. Our dear friend bleach/chlorine/sodium hypochlorite is a real superhero sanitizer, but has its limits. It doesn't know the difference from a leaf, pollen, tree branch, algae, bacteria, or insect. It just goes to work oxidizing it if it is in the pool.
do you still put in the "typical" 2-3 ppm?
No. What's important is the FC is in the target range. It doesn't matter if you had to add .5 ppm or 5ppm. The FAS-DPD test allows us to add only what we need with little waste. That's one of the reasons many of us say it is an investment that pays for itself in bleach savings. By keeping your FC in or just above target for your CYA, you're keeping your FC well protected from sun degradation while maintaining a responsible buffer of available/active sanitizer to oxidize/kill contaminants that would love nothing more than to green your pool and get you sick.
Pools, like pets, cost money. They need to be fed or they get sick, or worse.
As for how much money it costs to maintain your FC, now that's something we can work on! No matter what though, FC must be regularly replenished, either via SWG, bleach/chlorine, or
one of the other methods. Each method has trade offs and limitations. Most people conclude that either SWG or bleach is best for them. Those who go bleach sometimes upgrade to an automatic bleach pump.
To answer your specific question though, a 26,730 gallon pool requiring 3ppm added, if using 10% would indeed be 103oz aka 3qt1cup, and yes, that's most of the jug. The whole jug adds 3.75 assuming it is fresh.
$3.50 a bottle might be a number we can get down though, depending on your local options. Depending on water temps, a SWG could be cheaper if bleach prices are high in your area.
Important note - daily FC demand is highest this time of year. My bleach cost per day in the summer is 5x what it is in the winter. Contributing factors include: bather load, water temp, rain, UV index, insect load, summer organic debris (grass clippings, pollen, flowers, etc.), and such.