I just decided to cancel my pool service since I noticed I was paying $90 a month for about $10 worth of chemicals. I am starting this month to balance myself and was curious if my plan is correct. I watched them last summer and it seems like I need 3 things. Chlorine tabs, shock and muriatic acid. In the late fall and winter they only seem to be adding chlorine tabs so I assume when the temps go up i will need to shock once a week and add acid when the PH is high. Am i missing anything? Other than my local pool store, Leslie's, is there a better place to buy chemicals? Their prices seem ok. Thanks!