If your FC reading is 0, then you wouldn't have needed to dilute your sample to get a reading. Add enough bleach to raise your cl up to 15 and try and hold it there. In a pool this size, each quart of 6% bleach will raise your cl by 2ppm. Test 3x a day and each time, add enough bleach to bring your cl back up to 15. Run your pump 24/7.

Also, your ph is too high. Add some muriatic acid carefully in front of a return jet. Be careful not to breathe the fumes or splash any on you. Start with one cup and then let it circulate for several hours, retest and redose until you get it to 7.2. Your alk is high, but you can worry about that after the pool clears. Don't worry about a hardness reading in a vinyl pool.