I am having trouble finding test strips to test the salt for my pool. I just installed the SWG and was ready to put some salt in, but wanted to test it first so I don't put too much in. Walmart sells the regular test strips with the salt test strips for $18, but I don't need all of that. I just need the salt test strips or a regular test for salt. Where can I pick one up or what should I look for? Thanks.