well, heating it tends to make the product oxidize more, i don't think it will necessarily yield a weaker final solution, just don't go overboard on the heating, heat it just enough to get the shit dissolving....ive had some batches dissolve easily and others not so easily, so it just depends....and yeh, the cooler it is the longer it will take to dissolve, so just apply some slight heat and swirl it as often as you need