2 years ago I used pucks and found out the hard way about shock lock. Then, discovered the ammonia in pool the following spring. It was hard to clean, but I did it and changed my ways and now use BBB. Last season I used the BBB and had a great season. So I thought I had wised up last fall when I closed the pool, we have to winterize it because it freezes. When we closed, it had very little cya and no ammonia, nice looking clear and balanced. Drained it to jets, added closing kit. Over the winter the pool filled back up with water. This spring I opened the pool: 32,000 ig pool. It was cloudy and greenish with a lot of worms in the bottom. We have trees with leaves, but a very good cover keeps them out. Testing: Ammonia 6+ dark green, Cya 0, fc 0, Ph 5-6, Alk 80. Ammonia happened again?????Why
I shocked the pool with 4 bags of shock, added 1 1/2 box borax for ph, half an our later, 8 bottles pool chlorine 10% --no fc. Shocked the pool 4 bottles 10%--nope, added 1 borax and shocked 4 bottles, 2 bottles ,2 bottles. It took 20 GAllONS of Chlorine 10% total to get a fc reading!!!!!!!!!!!!!
My Ph went down again so I added more borax. I used a total of about 3 1/2 -5 boxes of borax, ph 6.8. I also started to add air to pool to raise ph. Three days later the pool is blue, cloudy but better. Ammonia 0, Cya 0, fc 3, ph 6.8, alk 100. I need to get some stabilizer in pool, and get the ph up a little more yet. Its getting there. But what is causing the ammonia?????? The Cya was very very low at the end of the season, I don't have any ammonia problem during the swim season, just really high every spring?????????? 
I shocked the pool with 4 bags of shock, added 1 1/2 box borax for ph, half an our later, 8 bottles pool chlorine 10% --no fc. Shocked the pool 4 bottles 10%--nope, added 1 borax and shocked 4 bottles, 2 bottles ,2 bottles. It took 20 GAllONS of Chlorine 10% total to get a fc reading!!!!!!!!!!!!!

