How long should it take to completely flood and drain an ebb and flow system? I'll tell you why I asked

Hi thank you for taking my question. Currently my ebb and flow table takes 12 minutes to completely flood. It's an active Aqua 550 GPH. I have it set all the way open. It takes 15 to 20 minutes to drain. Now I know about the correct height that it needs to have the tubing set at so it'll have a good fall rate. But even still is it supposed to take 12 minutes to completely flooded? And what is your time to completely drain? Thank you for your time.