OK, Your off to a good start. You have a good test kit and I would trust if over the pool store - I doubt the clerk there knows as much about chemistry as you do if you have read the Pool School. Anyway, have you found the Pool Calculator? If not, look in Pool School and click on the link to the Pool Calculator. You enter your pool gallons at the top where it says "size" and at the bottom you enter Trouble Free Pool, bleach, the pool surface(vinyl) where it says "suggest goal level." Then look at the line above where it says "Suggested FC level" and check the shock - if your prior calculations are accurate it will be 18. Anyway, whatever it is you want to enter it in the Target (or right) column on the FC line. Then in the Now(or left) column enter your current FC level. Be sure and fill in the other Now column blanks - particularly the CYA. You can then read how many ounces of bleach you need to add. This is how much you add to bring the pool from where it is now to shock level. Then in one hour test the FC level then insert the new number in the now column and calculate how much bleach you will have to add to get back to shock level. Do this no more frequently then one hour and do it as often as the rest of your life permits. The more you can keep bringing the pool back to shock level the faster it will clear. So if you have Saturday and Sunday off try to bring it back to shock level every hour -- you will see a difference. Also you can speed up the process by brushing often. This sort of brushes off the dead surface algae and lets the chlorine get to the live algae. You will also want to keep an eye on your cartridge filter as the algae dies and gets filtered out you will need to clean the filter. It will be a pretty intense few days, but if you keep at it, study Pool School, read posts on this forum, and ASK questions you will be very successful. If you have questions about the testing or anything else just ask them here in this thread. You will find there are some real experts here are very generous with their knowledge and more than willing to answer your questions. If you know how many gallons are in your pool add that to your signature and then we can help you double check your Pool Calculator results. If you do not know how many gallons are in the pool, there is an area at the bottom that will help you calculate the size. The easiest way is to divide the pool into sections - calculate the shallow end, then the deep, and then the transition with an average depth and add the three results. Again, let us know if you have questions and keep us posted on how it is going.