Flow

[Delphinus]

Originally Posted by Troy F

I don't quite follow the reasoning of slowing the water down in the sump to filter it. Once it's in your skimmer, it's in your skimmer and the volume doesn't change. If more water is changing over wouldn't it still get filtered?

I just mean that there's probably a point of diminishing returns, where increasing the flow through the sump beyond that threshold, does not yield results proportional to the amount of extra energy you put in to create that extra flow. (Am I making any sense? It makes perfect sense in my head, but translating it into Eeeeenglesh words is maybe losing something). Plus, increasing the flow through the sump increases the likelihood of microbubbles. So there's a comfortable range. Under the lower limit of that range, would be ineffective (because you're just skimming your sump), and above the upper limit, would be inefficient (note not "ineffective" - "inefficient").

Now if you want your sump to be the main source of flow for the main tank, and eliminating microbubbles, one method you may want to look into is the method of submerging the downspout completely, and then tuning the overflow (with a valve) to match the sump return pump flow exactly. Then no air gets drawn into the downspout, and, no air bubbles. The only thing is you need to have a secondary overflow pipe to drain into the sump in the event the valve gets blocked or something. I forget what this method is called, but I think it does have a name. If I remembered it I'd tell you so that you could search on it. But there have been a few to employ this method and they seemed happy with it.