• All filters function better with low flow rates per sft of filter area. This is ESPECIALLY true with sand filters.
  • All filters run longer between cleaning with low flow rates.
  • High flow rates tend to damage filters. High flow = high differential pressure which KILLS filter cartridges, especially modern 'high-capacity' cartridges with pleats that are too close together. High flow may damage DE membrane support grids. High flow WASHES SAND OUT of the filter during backwash, and PUSHES DIRT THROUGH the filter during operation on sand filters.
  • It is still possible to develop high differential pressure, across the media, with oversize filters but it's much less likely.
Is that enough? If you need more, you'll have to wait till later this weekend.

By the way, REGARDLESS of filter type or size, you need a WORKING pressure gauge to monitor filter ops properly.
  • NO FILTER should operate at over 30 psi absolute (unless it's the new-ish Pentair high-pressure sand filter).
  • NO FILTER should operate at more than a 7 or 8 psi pressure rise (clean to dirty). Cartridge filters should be cleaned at a 5 psi rise (old style) or 3 psi rise (new style with pleats too close).