reading and rereading all the newbie stuff...had the pool opened and treated on saturday and saw algae on the wall sides by monday...i had ordereda digital tester through him and he showed me how to use it..but told me i did not need to use the cya tablets or test for it...????? my cya level is ranging between 160 and 200 so tomorrow i start draining...my goal next year is to save the 400 for opening and treatment, especially since it obviously did not work...thank you all! it is a little overwhelming but i love the pool..