That traditional order of bottle-filling starts with what we call the most volatile to the least volatile. VOCs, SVOCs, metals, and filters is based on old research that used predominantly bailers for sampling. If a bailer is pulled out of a well, you want to take the most volatile sample first since it has the greatest effect of changing that sample with time. But if you’re pumping from a well at a low flow rate, under steady state conditions, and with stabilized indicator parameters then the bottle filling order no longer matters; what does matter is the flow rate. So if you start out at a flow rate of 500 or 300 mL per minute and have larger bottles to fill, fill those first, then reduce the flow rate and fill smaller bottles, and finally, pause momentarily to install the filter, and take the filtered parameters. So the old bottle filling order is still correct if you are using a bailer, but if you are using a low flow pump and a low flow approach, bottle filling order really goes from largest to smallest bottles.