Do I need to SLAM??

This is our third season opening our pool and we have never owned a pool prior to this one so a newbie in away. Late last season I found Trouble Free Pool and have been researching and applying what I have learned ever since. So anyway late last season I decided to switch to BBB method (was using slow release Trichlor tabs, powder Trichlor "shock" along with ALL the "other" bad chemicals because hey, I didn't know any better, lol and my CYA skyrocketed to 100 ppm, yikes) along with adding Borate (Borax for softer water and help prevent algae problems). Okay I opened pool about 1 1/2- 2 weeks ago, water is CRYSTAL Clear, Shocked using 10% bleach (Didn't have the taylor 2006 at this time so my OTO only showed combined chlorine was higher than 10ppm), brushed sides and bottom of pool, robotic sweeper swept up the little bit of particles on floor of pool, put solar cover on thinking good to go once water warms up. Check CC with OTO test and would add more bleach when it tested lower than 10ppm, well started thinking I was having to add bleach a little to often so ordered the Taylor 2006 kit. I have to admit I didn't really check my chlorine level for a few days while I was waiting for my Taylor kit to come in. Received Taylor 2006 kit tested water 5/18/15 FC=.5, CC=0, PH 7.5, TA 160, TH 250, CYA 90/100 (I have tested this several times it is high, I can't really just drain our pool by 60-70% and add new because it has to be hauled in and it is not cheap plus we just paid to have water hauled in to fill this pool 2 seasons ago so I'm living with this for now). Ok so at 1:30PM on 5/18 I added 448 oz of 10% bleach (that I had from last year stored in our shed) to bring FC to 25ppm (I didn't check FC again after adding to see if it actually went up to 25ppm) I checked FC at 8:30PM (after sun off pool and almost down for the night) on 5/18 and it tested FC=13.5, CC= .5 I rechecked on 5/19 at 6:15AM (before sun up) and FC read 10.5 (3ppm drop overnight!!) I added 64 oz of 10% bleach to raise FC to at least 13ppm. I rechecked chlorine tonight 5/19 at 8:15PM and it read FC=10ppm. Do I have a problem? Could my Bleach I had from last year lost some of it's strength? Do I need to SLAM my pool? I am at a loss, my pool is crystal clear but I don't understand why I am loosing FC so rapidly. Please any advice! Thank you