How to prevent water from spiraling down drain?

[FishDoji]

I recently installed a fiji cube overflow box on the back of my tank. It works great and I installed a gate valve to get the siphon. After tweaking the flow I have it pretty much in sync except every so often a "vortex" or spiral of air will form and some air will go down the pipe. Is there something that I can put in the overflow box or do to prevent this spiraling?

 

[Sisterlimonpot]

I recently installed a fiji cube overflow box on the back of my tank. It works great and I installed a gate valve to get the siphon. After tweaking the flow I have it pretty much in sync except every so often a "vortex" or spiral of air will form and some air will go down the pipe. Is there something that I can put in the overflow box or do to prevent this spiraling?

Are you limited to 1 drain? If so then it's almost impossible to set the gate valve to match the return flow. No matter what you do, you either restrict the flow too much and cause an overflow event, or you don't restrict it enough. Which is why it is crucial that when you restrict flow with a gate valve that you have at least a secondary drain that will allow for that regulation. On a bean animal design they call that the "open" drain that always has a trickle of water, but that varies. And on a herbie design [i think] they call it the emergency.

either way you're risking a lot by only having 1 drain with a flow restrictor such as a gate valve.

 

[Ippyroy]

I have the same issue. I wind up letting water go down the E drain in a pretty small trickle to silence it and to help stop the vortex issue.

 

[FishDoji]

Sorry I should have provided more info. Yes I have a Herbie. Currently I have a trickle of water going down the emergency pipe but there still seems to be a swirling of air into the main. I am hesitant to restrict the flow any more. Would a U bend PVC fitting fix this problem like a Bean Animal setup? Idk if my overflow box is big enough though

 

[Sisterlimonpot]

I have the same issue. I wind up letting water go down the E drain in a pretty small trickle to silence it and to help stop the vortex issue.

^^^ This. I just looked at your one picture of your tank, it appears that all you have to do is slightly close the gate valve a bit more and have water trickle down the 2nd drain.

 

[Sisterlimonpot]

Sorry I should have provided more info. Yes I have a Herbie. Currently I have a trickle of water going down the emergency pipe but there still seems to be a swirling of air into the main. I am hesitant to restrict the flow any more. Would a U bend PVC fitting fix this problem like a Bean Animal setup? Idk if my overflow box is big enough though

That clears things up. The first thing that comes to mind is to slow the sicce pump down and limit the turnover rate, that will prevent the turbulence. another idea is that if you don't have one, add a "U" shaped adapter onto your main drain so that it faces down which will lessen possibility of the vortex.

 

[FishDoji]

Nice! I will try those and hopefully get it running silent. Thank you all for the help on this!

 

[38bill]

I just went through the same thing with my Fiji ext overflow (aprox 4" X 6" X 7.5" tall). This overflow is small so the tank water flowing into it causes turbulence. I raised the emergency overflow drain pipe, shortened the main drain pipe and put a 90 deg fitting on it. I had to shorten one end of the 90 so it would fit in the overflow box. All this helped but I still had the water rushing into the overflow box and it made noise. I added a "T" fitting to the bulkhead (I removed most of the top of the T) and now the overflow runs completely silent. The bulkhead must be metric as I had to machine the PVC slightly to fit. Another fix would be just make a wider ext box so the inlet and drains are not almost right on top of each other.