Thanks for the welcome. I am not sure of the exact contents of the shock, its "Chlor-Brite" sold at Leslie's Pools. I have dumped so much of this along with bleach into this pool the last few days that it is almost impossible for me to believe it would take more. I have poured at least six of the large bleach bottles and twn pounds of shock over the last five days but I will continue on. I have been running the pump 24/7 for several weeks and although the water is pretty clear, the algea continues to grow. I was wondering if there was a reason that it wont hold its chlorine level that would make sense to me. I guess I am so used to seeing instant results from shocking that when little happens it causes me to think there may be another problem. Thanks for the response to my post!