Backyard Aquaponics
A place to discuss aquaponics

so, TCL, if I just have a couple of u-siphons going into my small overflow side tank, I might be okay.

Elginite,
Yea probably but make sure you check them regularly to keep from getting any bubbles in them.
I've had trouble with ones made out of PVC and elbows and then I installed the little check valves so I could suck air out of them but then had some of the check valves fail or bumped the check valve and broke it off of the pvc which of course immediately fails the no holes overflow by opening the hole in the top of it. Sigh.

If you already own a good quality U-siphon and box set up, I suspect you know as much as many of us about these things. I would definitely not trust a single no holes overflow on it's own as the only means of moving water. Always have a backup overflow. That also goes for the grow beds. Make sure to install an overflow somewhere so in case the syphons don't work for some reason, the beds won't make a mess on the floor.

My loop siphons work fine with only a couple inches drop. But the more drop the better. Especially with bell siphons.

Just happened I am using simple no hole overflow (U-pipe) joining my two aquariums.
It works reliable for more then one year.
The trick I have used is that at single end of the pipe there is a powerhead attached.
This pump is turned on regulary for a short time by means of 24h timer.
So most of the time overflow (pipe+pump) works passive - as desired.
But for a short time (can be a single minute) it works "active" then air bubbles are removed.
Thy drawback is that attached powerhead slowers the flow in "passive mode".