Bean Animal with Synergy Overflow Advice

[Channaman]

I know theres a ton of threads on this but cant get a definitive answer. Im running the synergy shadow overflow with the included U pipes. 1.25" for 12" and then reduced to 1" total run is about 2 feet with no 90s. Im running about 500gph reurn flow.

In short I cant seem to get a small amount of flow going through the open channel without breaking my full siphon. When I achieve full siphon - there is too much flow going through the open channel - so I slowly open the gate valve on the full siphon to take more of the flow. When I do that I lose full siphon and it starts introducing air. Its almost as if thats the maximum flow that line can take without breaking siphon.

Also note that when Im running at what I beleive to be full siphon, the water line in the overflow box is below the hole in the top of the U pipe. I thought it wasnt possible to achieve full siphon with that hole being above water but it is running quiet.

Im wondering if Im having trouble overcoming the 1.25" pipe or maybe my whole setup is off.

Any advice is greatly appreciated.. I will take some pics/videos as well.

Thanks in advance

 

[ca1ore]

Pics would help. My guess is that your siphon is not low enough in the box.

 

[FLSharkvictim]

I am in the process of setting up a new SCA Rimless 150 w/ a 20'' External overflow box and I got and one of there Synergys CL-44 sump which I plan on plumbing in the next few weeks.
I'm running mine a little different, I am running 3 1.5inch drains with a 1.5inch Spears gate valve / so no reducing on my drains. For my returns, I will be going all 1'' reduced down 3/4'' to a locline.
Running my tank with a Ectech Marine M1 and a COR20 Apex which will also be hard plumbed into my Algae scrubber. More info to come on my thread!