I guess 4 second pulses wouldn't be to bad.
Flow into SCWD SCWD TD Output Efficiency Switching Duration
150 gph 90 gph 60% 22 seconds
180 gph 120 gph 65% 16 seconds
240 gph 180 gph 75% 12 seconds
270 gph 210 gph 80% 10 seconds
330 gph 240 gph 80% 9 seconds
400 gph 360 gph 90% 7 seconds
600 gph 540 gph 90% 5 seconds
720 gph 660 gph 90% 4 seconds
Flow into SCWD SCWD TD Output Efficiency Switching Duration
150 gph 90 gph 60% 22 seconds
180 gph 120 gph 65% 16 seconds
240 gph 180 gph 75% 12 seconds
270 gph 210 gph 80% 10 seconds
330 gph 240 gph 80% 9 seconds
400 gph 360 gph 90% 7 seconds
600 gph 540 gph 90% 5 seconds
720 gph 660 gph 90% 4 seconds