I have a sand filter and put everything in the skimmer. As long as the pump is running no harmful concentrations should occur. Just be sure you keep circulation going until whatever you put in is dissolved. Personally I don't like dumping stuff right in the pool, especially solids, as there is a risk of the stuff laying on the bottom. Never used the baquacil stuff but me suspects you'll eventually regret it. Hope this answers your question.
Al