Hi Folks! Wish I'd found this forum much earlier! Our pool is 2 1/2 years old and this year has been a nightmare! Last summer season we kept going into chlorine lock. I deal with a local pool store for water testing and solutions. I was told this start up season we would need to drain or pool by about 1/3 and freshen the water again. (I was shocking twice a week, was having metal build up etc. ) Was becoming very chemical expensive. So... we drained the pool by about 3/4 and refilled. Took in samples and the CYA was way to high. Pool guy said run it for a week and bring in another sample. I did that yesterday and the franchise owner was working the shop. He tested... crazy high 160 cya levels. He says the employee that told me to partially drain is wrong! I should fully drain and refill to get it out of the pool and he will comp me the stabilizer to do this now. Now I'm currently completely draining and refilling. Ugh! I am using Bio guard tabs and it's easier on my husband's skin ( tends to have eczema). Wondering if I need to switch to the liquid chlorine instead. Feeling like I'm really over complicating the pool care. I have neighbors who have never changed their pool water...