On the far left is incoming water pipe split into 2 flexible(?) pipes where each goes to the inlet of each of the filters. Outlet of both filters are joint to each others with a Tee connector at the center. Water coming out from both filters goes out through the center output of the Tee.
On one hand, I think it's good idea due to standard 10inch filters are being used here which I think kind of underwhelmed for outdoor POE filter, so it helps with filtering load by having 2 filters doing a shared job at the same time and also prevents water flow slow-down when one of the filters gets heavily clogged over time. On the other hand, I'm not sure if there's drawback or pitfall I fail to see which makes this kind of setup a bad practice
Best Answer
This is a pretty common setup to get high flow from smaller, cheaper filters. Two 10 gpm filters can be used to effectively get 20 gpm overall flow.
In this particular install the flex pipes, mix of galvanized and brass parts, and lack of shut-off valves and pressure gauges screams amateur installation to me, but I don't see anything that prevents it from working.