Overflow pipe to small?

[snip84]

I made a overflow pipe and it doesnt seem to work properly since it doesnt handle the return pump flow..which is set at lowest already. Overflow pipe is 20mm and the return pipe is 16. do i need to use a bigger pipe? will post pictures soon...

[evilc66]

What's the flow rate and how is your drain set up (open pipe/bulkhead/strainer, durso, etc...)?

[spinycheek]

It's hard to tell without a flow rate, but a larger overflow never hurts!

[snip84]

Its a Tetra WP1000 return pump, open pipe to the sump, set to minimum. Its max flow rate is 1000l/h, i cant find the actualy flow rate. The high is about 1m. I had a overflow box before with the same 20mm pipe and it could handle the max. speed of this pump, now this pipe overflow barely does handle the minimum. Somethings wrong i guess..pictures attached.

 

http://s3.postimg.org/rflogrztv/20151009_201030_1.jpg

[evilc66]

Is that 20mm on the inside diameter, or outside diameter? From the picture, it looks tiny. Also, what's that setup on the top of the pipe?

[Benny314]

That's 20mm external so the internal will be like 16mm, which is far to small. It might handle it if it with more syphon pull, but as an overflow loop like that you'll probably need a bigger bore pipe to get the results you want. You could always try increasing the drop outside of the tank to create more gravity draw on the syphon. But you may run out of height before getting the draw you need.

[snip84]

I just ordered a 40mm pipe for the overflow. I hope that Will fit...