Overflow help

[squidworth]

I have a 75 gallon folr tank with a hang on overflow. It has about an inch drain line out of the box then into about 1.5 inch hose to my wet dry.
I had to by a new return pump (600 gph), and it seems that it is just a little too much flow. It will suck my sump down then blow bubbles.
It is an EHEIM 1260. Can I put a valve inline to control the flow without hurting this pump?
Second, how big of a line do I need on the overflow to keep up with this GPH?
I am currently preparing to buy a new overflow, but I have a real rig job going on to keep this working for now. Direct siphon hose to supplement the outward flow of the tank. This is a really risky set up for the short term.

 

[reefforbrains]

absolutley do anything you like but i would very strongly advise NOT to run direct siphon without a watchful eye.
I always wonder myself how much you can choke a given pump without killing it. Gating it by 10% shouldnt hurt, but some cut it back by 30-40% and no matter what i hear that just seems like it overworks the pump and shortens the lifespan. Why not call the manufacturer for a rate you can safely cut it back to?. That would answer from the horses mouth

 

[squidworth]

Well I have the intake that will draw air fairly soon on power failure, I would say a little wetness would happen, but wetness none the less.
Good suggestion on the check with the pump company.

 

[hydra]

You don't have to create any back-pressure on your pump in any real way. Just T-off your return line and put a ball-valve on a line back into your sump. This way any extra capacity can be controlled with the ball-valve to bleed off that extra capacity w/o stressing the pump. An alternate solution would be to send the secondary line to something that requires a slower gph like a UV sterilizer for example.
-Jerry C.