I will be plumbing in an Intex SWG when I open my pool up this year. We have not used a SWG in the past and I know you need to check salt levels to start. What do I need to use to check the salt levels? I saw Leslie's has test strips but they are expensive (10 strips for $12.99!). Is there a better (and cheaper?) way? Also, is it listed somewhere as to what salt to use and how much? I thought I had read it before but now I can't find it. Thanks!