Mag 9.5 & 2 Eshoppe 800 GPH Overlows

[kube]

Ok heres what baffles me, I have a 55 gallon tank with a 800gph over flow and a 9.5 mag return pump on the return i have a tee that i can open to have less flow to the dt and recirculates it to the first compartment of the sump. That said i have to have that valve almost all the way open to keep it running without overflowing the DT, no big deal for now
So i'm setting up a 125 gallon and i thought i would use the one over flow i have and buy another for a total of 1600gph that they are rated for
And recycle the mag and use it since its only rated at like 950 gph with no head pressure i should be plenty under the 1600 after you add head pressure. So i do a test run on my 55 gallon tank today i add the other over flow and close the tee valve on my return so all water is going to the dt.
I cant believe that the two overflows can't hardly handle the mag 9.5, water level rises above the black overflow boxes. It never overflowed the tank, just raised above the boxes and stayed there for like 30 minutes till i stopped the test.
How is that possible they should be able to handle up to 1600gph ?
I open the valve just a hair and the water level lowers and water actually starts to cascade into the box like it should. I don't want to add another overflow
Any thoughts here as to why they cant handle the mag 9.5

 

[truehle]

Originally Posted by Kube
http:///forum/post/3030087
Ok heres what baffles me, I have a 55 gallon tank with a 800gph over flow and a 9.5 mag return pump on the return i have a tee that i can open to have less flow to the dt and recirculates it to the first compartment of the sump. That said i have to have that valve almost all the way open to keep it running without overflowing the DT, no big deal for now
So i'm setting up a 125 gallon and i thought i would use the one over flow i have and buy another for a total of 1600gph that they are rated for
And recycle the mag and use it since its only rated at like 950 gph with no head pressure i should be plenty under the 1600 after you add head pressure. So i do a test run on my 55 gallon tank today i add the other over flow and close the tee valve on my return so all water is going to the dt.
I cant believe that the two overflows can't hardly handle the mag 9.5, water level rises above the black overflow boxes. It never overflowed the tank, just raised above the boxes and stayed there for like 30 minutes till i stopped the test.
How is that possible they should be able to handle up to 1600gph ?
I open the valve just a hair and the water level lowers and water actually starts to cascade into the box like it should. I don't want to add another overflow
Any thoughts here as to why they cant handle the mag 9.5

I have near the same situation, an Eshopps 1200 (1000 gph overflow) with the Mag 9.5, and I had to choke back my pump quite a bit (30-50%). I had a lengthy and very educational conversation here.
1. Make sure you have unrestricted path from the overflows to your sump. Small pvc diameters, elbows, valves, etc. can all cause backup and slow the pathway from overflow to sump. The key is that ANY restriction of flow will cause backup in the overflow lines, and will severely slow the cascading water. Even the sponge filters that Eshopps supplied will slow the flow rate.
Water traveling through overflow lines is mixed with air, and does not flow as smoothly as a 100% water filled pipe. Its great for aeration, but not flow.
2. The higher the water level in the prefilter box compared to the level in the outside overflow box the better. The pressure differential will increase volumetric flow rate in the siphon u-tube. However, you can run the risk of overflowing the DT if your not careful when starting the pump.