Thanks for your help - - the pool is clear, I hit the boost on the SWG to shock it & it ran for 8 hours - but it says to measure copper because it will turn blonde hair green if copper is too high (have 5 blondes here) - I have the Intex texst strips, but the chlorine test strips are so unreliable that I am not comfortable with their copper test strips. Where can I find a reliable copper test kit? I thought to avoid boosting with copper ions, I would shock it with OTC bleach (is that a good idea?) - how much bleach would I have to use for a 2100 gallon pool? How long do we have to wait after putting bleach in to shock do swimmers have to wait?