I have the same issue. I have installed check valves to assist in draining. I have played a lot with timer settings with no luck. I agree it seems to take more time to drain than fill. I actually changed them back yesterday to a shorter time so the on screen indication matches to the bag, e.g. 1 to 1. I did have them set longer so they would run longer during the empty process. But with them set this way I didn't really know when they were 1/4 or 1/2, etc.. I would have to guess. IMHO it is easier to have everything 1 to 1 when switching from wake boarding to surfing. I end up having to run the empty cycle again on the boat ramp. This gets all but a small amount out. I do think the check valves help. I think my issue may be that the bags are getting "wrinkled" up near the drain port and it blocks the water flow a little. I have the 900 Sumo's.