Ok, I have a 200 gal. wet/dry on my 150 gal. tank. Because of the wet/dry I have two U tubes in he drop box. One or the other keeps breaking syphon. How can I stop this from happening?
Is the flow rate fast enough, or all the bubble get trapped and break the siphon? You can try to see if the siphon tube is the right size (too large->low flow velocity->trap bubbles-> siphon broke, but too small will not keep up with the pump)
If it is always like this, then you may need to install an AquaLifer pump at the to of the tube to get the trapped air out constantly, or get a venturi powerhead to do the same thing.
I've had this problem ages ago when using dual U-tubes. One seems to break more often then the next. I had always suspected that it's because they weren't performing equally due to water level and pressure gradient differences when two are used together. Not sure though.
Back then, there was no such thing as the Aqua Lifter pump (at least not in the US). Many people report they work well to evaculate trapped air in the tubes.
