This is debatable, but in my opinion you should place the filters AFTER the tank, for two reasons: 1) service on the filters will be easier in that position; and, 2) it is better to allow your pump relatively free flow into the tank, where pressurized water can then flow into the filters. That is just my opinion based on general plumbing knowledge. I haven’t installed more than a few of these systems, as we have very little call for them in the SF Bay Area (the ones I installed were in rural areas of Napa and Solano Counties).
NtP