Now, the first reason you shouldn’t be combining these types of e-juices is that each of these types requires different coil resistance levels. What this means is that they are vaped at different wattages. In fact, freebase e-liquids need to be vaped at higher wattages, which means that it needs less coil resistance. The opposite is true for salt-based liquids, as these work best on lower wattage vapes with higher coil resistance levels.