I had a liner change ,a sand change bought all from same place about 800.00 total installed then the told me after i filled pool up and tested water i needed 8 lbs of calcium booster (i have a vinyl pool) 4 lbs stabilizer 10 lbs of chlorine pucks then i found this site i have learned that i didn't need calcium booster due to vinyl pool the pucks add stabilizer and the 4 gallons of pool shock is just double strength bleach (12%) i bought a liner ,happy bottom, wall pad paid for install then the still wanted to get every $ i had in chemicals !!! It pays to do research thanks guys you have opened up a whole new world of pool care and allowed me to put my wallet up.... Again thanks will need help with test kit .. Again thanks lots!!!!