Calcium Chloride does not have an effect on pH. The chloride ion is neither acid, nor base. Calcium Hydroxide (kalkwasser) however is a strong base with a pH of 12 and will negatively effect the pH of your tank if added improperly. If you want to use Kalkwasser you have to drip it into a sump, but if you want to use calcium chloride, you can just dump it in