It's just one for your first dose to go from 0 to 12FC. In an hour you'll test your FC again. You'll add what you need then.
For example, Add your first dose. (To get to 12FC)
In one hour you test and find that it went down to 8FC. Put that in pool math and it will tell you to add 45oz to get back up to 12.
Another hour goes by, check FC. This time it came down to 10. Pool math will tell y ou to add 22oz this time to get back to 12.
For the examples I entered your pool volume in pool math and used 12.5% for the bleach strength.
At first it it will consume the chlorine more quickly. At some point you'll do a test and it will have only gone down a little. That will be when you know you can start stretching out the testing.
You don't *have* to test and dose as often as 30 minutes to an hour but the more often you can do right at first the quicker you can get to the point where it will start to hold longer.
You'll be able to start stretching out the tests. The goal is to do your best to keep it at SLAM level as much as possible.
Your testing is going to tell you how much you need to add each time. It won't always be the same especially right at first.
Just remember 12 is your SLAM level so you're getting it there and then maintaining that level until the SLAM is completed.
Is it starting to make sense yet?
*side note* I was worried when reading because I thought you were worried about using so much. Then I realized you think it should need more. The pool store method would have you dumping buckets of "shock" in the pool to more or less nuke it. We're much more controlled here. The CYA/FC chart along with the recommended shock level in Pool Math will give you the most effective level to kill algae and at the same time not risk damage to your pool. You'll be using plenty of chlorine...it will just be in smaller doses as you maintain a steady effective level rather than all at once which sometimes shows quick results but is the same as stopping a prescription antibiotic when you start to feel a little better instead of waiting until the end of the prescription. The purpose of the SLAM is not a big quick kill off but a steady effective level until you're sure nothing is hiding and waiting to pop back up when you go back to maintenance levels. Best of all, it works!
