Quote Originally Posted by waterbear
...Have you been putting in the algaecide?

...I don't know how your pool store is testing for it but if they are using a drop based kit for H2O2 such as one from Taylor (K-1725) then the results should be accurate.
I put the algaecide in each week as normal.

I don't know what each of the pool stores uses for test kits, but here are the shock level results from all 4 of the tests:
- My LaMott test kit: 150 (drops-based)
- My Taylor test kit: 35 (drops-based)
- First pool store: 127
- second pool store: 45

There seems to be two different methods for calculating hydrogen peroxide shock level. Still, all tests agreed that the shock level was adequate.