Hello, I'm starting to get low on my R-0871, as I'm on my 3rd SLAM in 2 months, and while I see I can order both the R-0870 + R-0871 from tftestkits.net, I'm not low on R-0870, and I can get R-0871-C from elsewhere for considerably cheaper. The full product name is advertised as "Taylor FAS-DPD Titrating Reagent (Chlorine) 2oz R-0871-C"