I bought a drop checker, from e-bay, that should be arriving soon. I dont think it's going to come with instructions but I've done some research and think I know how to get it going. Fill it half way with 4dkh solution, add the regent, put it in the tank just below the surface and let it do its thing. My question is about the ph regent. I've read that I can use the ph test solution from my API kit. Is that true? If so, how many drops should I add?