When I was saying the word curve I meant the pump curve. You can draw one based on the data points on that table that you looked at. Here is a page that talks a little bit about pump curves.
The drawing there is pretty poor, but it gets the point across.
His particular pump would be closer to the RIO 1100 than the 800. It has the same shutoff head and close to the same runout flow.
That particular one gets about 62% of its max flow in pkillur's case. Adding in any head loss could possibly take it below 50%
I guess I'm used to dealing with much larger pumps. The larger ones on that site support what I had said earlier.
In any case, the second paragraph of what I had said still holds. With all of the flow created by the filter pump, it would not take long for the dechlorinator to be evenly spread around the tank. Doesn't have to go through the pump to make it mix. It's the flow and turbulence in the water created by the pump that matters.