I just installed the SeaEra QC. Suspect similar flush flow rates. I tested the flow rate and found 1/2 gallon (approximately a full bowl for the smaller marine
size) in less than four seconds. This equates to about 8 gallons/minute. I plumbed a dedicated 1/2” hose from the discharge of my water pump
to the toilet and the incoming cannot keep up with the flush rate. Fortunately, I opted for the manual control. My solution as Peggy said is to pre-fill the bowl and then suspend the flush when the bowl empties. Re-fill and flush a second time if need be. One reason I selected the manual control is that I understand the default setting on the automatic control is 8 seconds, which I see is way too long.