Upgrading filters is ALWAYS a good idea. Even so the 2 speed works better with sand filters.

The slower the flow, the better the filtration with sand. 8 hours on LO will produce higher water quality than 4 hours on HI . . . and will use less than 1/2 of the electricity!

With the larger filters, you won't need a discharge throttle valve, but will definitely need to backwash on high.