pump too strong?

[gift05]

I'm using a hailea 6530 pump 1750l/h flowrate with the head at about 1.5m high. Using a IBOX 800 with max 600g/h rate to drain the water to sump. But when i turn on the pump , my sump is almost drained of water and its clear the overflow box cannot cope with my return pump.

so here's the thing. i know for sure 600G>1750L. so either hailea is understating their flowrate, or my i box is really not doing 600g/h.

what do i do now? i really like the amt of water cycling thru and will not be really happy with downgrading to a smaler pump. Looking for a awy to let more water into the overflow box to be drained. Any ideas? except putting more syphon tubes cuz there ain't no space alr.

[lightningstrike]

check ur u-tube. there might be air in it, siphon might be broken.

[gift05]

oh yes yes! its fixed now. it just took some old school mafia style persuasion. I stuffed the return pipe down the overflow's syphon pipe and run the pump for awhile. soon you'll hear some gurgling and woala its done. Thanks a million my fren =)