I have a problem. When I start my syphoning from my tank to my over flowbox it either sucks all the water from the box that sits in the tank or the return pump pumps more water then the overflow box can handle. The pump is a quiteone 1200 model which is at 296gph. I am using to plastic tubes to syphon 1/2 and 5/8in tubes. I am beginning to think my overflow box is to big for my tank which is 29gal. Need help please.

sounds like your return pump cant keep the water level high enough to keep the overflow box syphoning. you might want to try a bigger pump. depending on your overflow rate (how many GPH you box can handle), you should try to match that as close as possible to the return pump you are using.
example ... if your overflow is rated at 600 - 700 gph the a mag 7 return would keep the water level about right. of course you need to subtract head loss and elbow loss, but a mag 7 would work in the example.

I fixed it. It took 2 hoses to to keep up with my return sump. I just have to get a longer hose so that if the power goes out, when it comes back on I dont only have one hose syphoning.

cool, good work man, that was fast

lol yea I have a baffle in my overflow box, it is really big, anyway I put the 1/2 tube in there and the 5/8in hose directly into the main part of the overflow box and that did the trick. thanks