How can I increase the flow through my HOB Overflow?

[happyhourhero]

I run an Eschopps PF-800 overflow and have for about 2 years. I moved and cleaned my return pump and it is now pushing out more water. I used to be able to set it so the water dropped about 1-1.5" into the in tank side of the overflow box which helped a lot with surface skimming.

Now, it only drops about .5" below main water level. Is there any way I can increase the siphon speed? I have started and restarted the siphon several times and there is no air or blockage of any kind.

 

[saltyfilmfolks]

I run the same overflow. I think unfortunately you have to add more grates to in thank weir. I cant run the two tubes in tandem no matter how high I run the variable return pump.
Are you running one tube or two.

 

[happyhourhero]

I just have one tube. Would a larger diameter tube help you think?

 

[MaiReef]

If you use filter socks, they can hold up the siphon. The other option is to put a valve on your return line. I used to use that more when I had an A/C pump

 

[saltyfilmfolks]

I just have one tube. Would a larger diameter tube help you think?

I would assume so depending if the slowdown is in the internal box.
It would be a cheap way to test it...

 

[happyhourhero]

Thanks guys, I just ordered the one size up and will report back when I get it.

 

[happyhourhero]

Forgot to update this. The larger diameter tube came in and my flow ended up not being able to keep an air bubble from forming in the tube. I went back to the tube that came with the overflow and have been able to keep the surface skimming where i want it if I clean the tube once a week when I do water changes.

 

[wkscott]

I have the larger model Eshopps dual tube overflow box. In order to prevent airbubbles in the tubes, I put a very course sponge in the box right under the slits, but not actually blocking the tubes' inlets. This prevents the cascading water mixing with air and going into the tubes. A quick and easy fix and prevents air from breaking the siphon.
Thoroughly rinse and clean the sponge at each water change.