Quote Originally Posted by chem geek
I think we misunderstood each other.

When I said that slowing the flow would lower the efficiency, I meant slowing it down from the pump side with the already slowed down flow that is in the cell itself. In other words, the cell has already slowed things down for higher shocking effect and optimum efficiency with higher CYA to bind the chlorine, but if you were to slow down the pump a lot, then wouldn't there be a buildup of chlorine at the plates because there wouldn't be enough flow to sweep it away?

In other words, I figured that the salt cell had already designed into it the proper amount of slowdown for high efficiency and having a flow that is much higher (wouldn't build up as high a localized chlorine level to shock) or much lower (would build up too high a chlorine level near the plates to be efficient) would be less optimal.

Richard
So in a two speed system, one could theoretically expect higher "cell shock" at low speed, or more overall chlorine getting into the pool for a given run time and duty cycle at high speed. I expect the difference is probably not very noticable by the average user. They will still just set the duty cycle control maintain the desired chlorine level as they always have.

In any event it is all very intersting!