Simmons99, I'd say anything is possible. I usually run the filter 10am-4pm (10-6pm when it's hotter) and check the chlorine level at random times - but always after the filter has started.

Once I clear up my bloom, I'll experiment with this and see how much variation I get. My SWG has been running at 36% so I didn't expect large swings.

I've also been meaning to change the timer settings so the filter would run in two time blocks, which would also keep the Cl level more steady. Guess I'll get "around to it" very soon, especially with cooler weather and shorter filtering time on its way.