Yeah, you probably need a good kh gh test kit. Strips are unreliable. Sera makes the best kit. Water drop tests. The problem with trying to adjust your ph, gh, kh is consistency. For most keepers it really is not the way to go. That requires constant testing, constant adjustments, constant adding amendments. I have breeding cories in slighting harder water than you. They will adapt. I have 4 species. Panda is one, Habrosus is not. According to one of the online places I buy them, ph on cories goes from 5 to 8. With hardnes following. You really should have no problem