I searched previous threads and got carpral tunnel from scrolling. If there is a thread that anyone knows of that answers weather this is too much flow or not please link me and I won't waste webspace.

Other wise, is this too much flow? I want to run a pump that is rated at 1750 gph on a 75 gallon that would be about 23 x water change over cycles per hour. I want to route the returns not only at each end of the tank at the surface but also drop some internal plumbing that I will burry under the sand and use as power heads for flow similar to the builds that ReefOne has done. These will all be interconnected to the return pump kind of like a combination (simulating closed loop and) open loop.

Corruption, you explained that running this external pump would decrease reaction time in my sump but I guess I don't understand how that would happen when compared to a traditional in sump return pump. I am planning on plumbing the external pump straight from the sump where the drop in return pump usually goes. Could you explain this? I would think that pushing 1750 gph into the tank would push 1750 gph through the sump and refuge where the filtration takes place. I can only think that 1750 gph is too fast for the bacteria to actually have time to work when the flow is too fast. I also think that gph may be a little over rated and that the total volume of water is constantly moving towards equalizing concentration levels (ppm thing) and that it really boils down to some decent flow with a great filtration system.

I need to figure this out this week because I am ready to drill two 2 1/2" holes as drains if I use the external pump but don't want to make a mistake.

Thoughts?