how to reduce flow in sump?

[Drummond]

I'm in the process of putting together a new sump, probably about 30g. My return will be pumping 750 gph from the basement to the DT. I haven't decided on an external panworld or an internal waveline dc pump. I want the skimmer section flow to cut in half, maybe 325-375 gph. How would I go about doing this? I'm new to sumps. Thanks for the help :)

[RocketEngineer]

My question is why? Flow through the skimmer section ensures that the water in that part of the sump has the same level of nutrients as the water in the display. You don't want the display to have a higher concentration of nutrients than the sump because then the skimmer can't pull what's in the display out of the water. With enough flow the entire volume of the system is exposed to the skimmer, not just a small portion resident in the sump.

[Drummond]

My question is why? Flow through the skimmer section ensures that the water in that part of the sump has the same level of nutrients as the water in the display. You don't want the display to have a higher concentration of nutrients than the sump because then the skimmer can't pull what's in the display out of the water. With enough flow the entire volume of the system is exposed to the skimmer, not just a small portion resident in the sump.

I'm still looking for a skimmer but there seems to be a pretty big price difference between one that can handle 375 gph and one that can handle 750 gph? Several hundred dollars unless I'm looking at the date wrong. I'm just trying to stay within a budget.

[ca1ore]

The amount of water flowing through the skimmer section has no bearing on, and no relationship to, the pump rating on the skimmer or the size tank it is rated for.

[RocketEngineer]

What the skimmer can "handle" has nothing to do with the flow past it. All skimmers a multi-pass design whether using the skimmer section or the skimmer body, they all work the same. Also, they all pull around 30% of the compounds out of the water no matter the design.

There is no one standard used to rate skimmers which makes picking on a challenge. I go by the manufacturers specs and use about 75% to 50% of their rating for my display. For example, my current skimmer is rated up to 200g but I'm using it on a 125g display with no problems. My last skimmer was rated for 150g and I had it on a 75g display.

[DaveMorris]

I agree with the above. Too many people have this incorrect idea that your skimmer should match the flow through your sump, but never seem to address the fact that unless the skimmer is gravity fed, a large portion of the water will flow right past the skimmer.