Help!! Finally! I added water to the tank today.

Is your drain pipe below the sump water level, or above?

Is this a reef-ready tank with a Durso standpipe?

Is there a hole on the top of the elbow on the top of the standpipe elbow?

What brand and model pump are you running?

So you have a control valve on the return pump?

Pictures?

 

Durso standpipes are finicky and I'm not really an expert on them. I'd just be guessing so someone else might chime in here to help out.

If it is filling up and then the level drops suddenly and that cycle repeats, then it sounds like it isn't tuned right. What I think happens is that as the water level rises, the flow increases until it flushes out and then sucks air in and gurgles. The water column inside the pipe pulls the water down faster as the water level rises until it exceeds the water rate coming into the overflow box. So you have to match the rate of flow coming into the overflow box.

Logic tells me that you would want to adjust the standpipe lower in the overflow box so that the flow can't get pulled in faster, meaning, the water column within the standpipe hits a maximum level and that maximum is below the incoming flow rate. If you raise it higher, then the maximum level increases and you should get a faster cycling of flushing/gurgling/filling. But I might have the reversed.

Point is, mess with the standpipe level. You might have to mess with the return pump valve too.

Adding the airline I don't think is necessary if you can adjust the standpipe properly. It's kind of a tuning process. Adding the airline lets air intrude into the pipe and this slows the rate of flow and prevents the siphon effect. But if you slow it down by adding the standpipe, then the water flow into the overflow box overwhelms the pipe and closes it off and it siphons until the open elbow is exposed to air.

Hope that helps....

 

A durso should have a sliding standpipe, one part sleeved over the other. If it's a cut pipe, then you would want to adjust the pump flow

 

Gradual bends will help prevent the drain line from "closing off" and will generally increase flow, as 90 degree bends create a lot of turbulence points. But I'm not sure that's the issue he's having. @leymas what does your drain plumbing look like? Can you post a picture or two? That might help clarify/pinpoint the issue

 

You definitely need to get that loop out of there. You could end up with an airlock in there at some point and without enough pressure from the return to "flush" it though as @Zach said you could end up with a flood.

 

gurgling gone?