overflow acting funny

[Absint Reefer]

I have a 110 high with like a 30gl wet dry and the overflow box in the back is filling up then draining half way then repeating I would'nt mind but it makes a gargle noise somthing firce anyone have any ideas how to fix this?

[Dawman]

Do you have a built in overflow or a HOB overflow ?

[Hop]

Sounds like the vent hole in the durso/stockman is plugged up... If you have a different set up, we might need some more details:)

[Satori]

IME, that's caused by one of two things:

1) The vent hole isn't adjusted properly.
or
2) Too much flow.

[Absint Reefer]

it is a built in overflow and when you say vent hole what are you talking about? I'm sorry I know very little about plumbing and overflows

[just dave]

If it is an overflow with just a straight drain pipe a restriction in the drain line ( kinks, bends, loops, outlet underwater...etc.) or pump size vs. drain size is mismatched will cause this. In each case what is happening is that more water is being pumped in the tank vs. what can comfortably drain out of the tank through your current drain configuration. As the water being pumped in can't get out at the same rate it starts to back up. As it backs up the water level reaches a point where you get a "flushing" effect and it rapidly drains down and the cycle starts all over again. See if throttling back the return pump helps. If it does and you don't want to keep the pump throttled back you will have to address the restriction(s) in the drain.

[Satori]

<a href=showthread.php?s=&postid=10250044#post10250044 target=_blank>Originally posted</a> by Absint Reefer
it is a built in overflow and when you say vent hole what are you talking about? I'm sorry I know very little about plumbing and overflows

If you're using a durso style standpipe, I'm referring to the vent hole at the top. Is that what you're using, or is it something else?

[Absint Reefer]

If you're using a durso style standpipe, I'm referring to the vent hole at the top. Is that what you're using, or is it something else?
yes it is

what's weird is that the tank has been up and running for 3 months and never did this before I never messed with the pump or the overflow, is this common

[Satori]

In that case, check the vent hole for salt creep clogging it.

[Absint Reefer]

if the vent hole is the little hole on top of the overflow going down into the sump then thier is no clog