I have one, I no longer use it. They do overlap, imagine a square wave. The first outlet is a long period on, then long period off. Second is short on, off, third is short off, short on. The reason I quit using it is it destroyed 5 rotating powerheads and 4 aquaclear powerheads in 1.5 years. I got tired of repacing the power heads. It seems to destroy the magnetic drive that runs the impeller. I use it now as a extension cord for my bird light. It is adjustable to long or short sequence. I always used the longest sequence because I thought the constant on/off would tear up powerheads, I did not expect it to do so that quickly. This is just my experience you may have different results. However you may want to return it because I can see no reason why you would have a different result. If it had the soft start feature it would be a great idea. It does not. I hate to be the bearer of bad news though I hope it helps you, so you dont have to waste the money that I did. Steve