If you are going to do the dilution method, you need to buy some distilled water.

Better yet, go ahead and get a good test kit. We recommend the Taylor K-2006 or 2006C. But, since you already have the K-2005, you don't need to purchase the entire kit. You can just buy the K-1515 which will give you the component that your kit is missing which is the FAS-DPD. That is the part of the test that allows you to test high chlorine levels. You can find it in the Amazon link in my signature.

Best to test in the evenings after the sun is off the pool and don't ever let your chlorine get that low. Unless you like algae!!