overflow gurgling

[r2d2]

Hi all, I make a large water change, 30gal on my 75gal. Also clean my powerheads and overflow box. Tanks is a cornerflow with a durso piping.
I also shorten a little my drain flex hose in order to rise just 1" filter sock.
But after doing this averflow start to gurgling and water level is fluctuating. What happened?

Greetings

[corrado007]

There is a little air hole on the top of the overflow typically. You can check to make sure that it's not clogged up by salt creep, algae, or something else. That can cause gurgling. I've also had green hair algae grow on the pipe in the overflow since it's so close to the lights. It's grown over the air holes on the sides of the pipe and caused gurgling sounds before on my tank in the past. Hope that helps and hope the solution is that easy for you.

[r2d2]

I already check that top hole, its not clogged. Lateral hole is also clear of algae.
The strange thing is that this morning everything was very quiet and after that waterchange- cleaning session, gurgling started.

[corrado007]

I've also had some gurgling after waterchanges that seems to go away after a short while. I'm not sure if some air gets trapped in the overflow somewhere or what but when it happens it seems to clear up in a few hours. I'd give it some time and check back in the morning unless you think it's a problem and not just annoying.
Can you tell where the gurgling is coming from? Up top where the water goes into the durso pipe, where the water flows through the teeth into the overflow box, or down below where it goes into the sump?

[Jeremy0322]

I would let it sit for a day or two and see if it works itself out, sometimes it just needs to find that equilibrium again after the water level goes down and back up that much.

[BigAl07]

I've also had post "Clean/Changes" gurgle and it went away in a day or so.

[Frankie]

You can totally silence an overflow by adding a gate valve to the output end in the sump and dialing it back until all the tubes are filled with water with no air. This will completely silence any overflow. It must be a gate valve, not a ball valve because ball valves restrict to much. That is why people have problems dialing in ball valves.
With this method of filling the plumbing completely you need to seal off any air vents you may have in your plumbing or it will not work. THis means that your return must be at the surface so the tank does not siphon out to much water in the case of a power outage. That is ok, return water is not for flow anyhow and should be used as a means to agitate the waters surface for optimum oxygen saturation.

[r2d2]

Is there any way to pull out air in pipes? Or just wait? This momrning gurgling is still present.
Sound comes from lateral hole in durso pipe, nor overflow teeth, no sump income.
Greetings

[r2d2]

What if after cleaning flow is more than before and overflow can't handle that flow?
Will this cause gurgling and water level swings?
My overflow is rated 700gph and using a Mag9.5 with 800gph@4ft.
Greetings

[BigAl07]

Originally Posted by r2d2

What if after cleaning flow is more than before and overflow can't handle that flow?
Will this cause gurgling and water level swings?
My overflow is rated 700gph and using a Mag9.5 with 800gph@4ft.
Greetings

If that was the case then you'd have . . . "Wet Floors".... The over-flow is probably handling more than it's rated and/or the pump is pushing less than it's rated.

[r2d2]

That make sense... Im breaking my head to figure what could happened. Im going to make some experiments with air and water over durso and see what happen.

[r2d2]

When I installed filter sock, hard ring was to close to sump surface so it overflows quite often so I rise it about 1" to force all water go through sock.
Its probabily that sock is too small and is acting as a bottle neck?

[r2d2]

Ok, I dont want to claim victory but feel it very close

Afetr spend all morning reading articles and google a lot of things, found a good option.

Theory begind this is: when water speed is very high inside piping a large suction force develops at pipe entry so it starts to drawn all water left in overflow box and when water level reaches lateral hole in piping a huge gurgling sound is produced.
So... you need to slow down water or let it suck more air in order to avoid water level to drop.







Just have to insert an air tubing in drain pipe to allow more air get into pipe.
Tubing is inserted just 1". System made two or three cycles and then run as smooth as always.

I checked it for about 45 minuntes and not a single gurgle came out.
I dry sump rim in order to see if any splash occur.

Here you have sock...



Its not everflown and now all gently water are being filtered as intended.

BTW: Have you looked at my Catalina T5HO fixture? Shiny ha?

Here is a pic of another weekend change: Fuge with sand, LR and Chaeto.



Greetings

[BigAl07]

Arturo I assumed you already had the "Vent Line" on your system. That's a good place to start "tuning" an over-flow.

Good work.

Yes very shiny fixture! aren't you thrilled with it?

[r2d2]

BigAl, yes, system already has a vent line. In second pic is almost unnoticeable because fixture leg is blocking it.
Last night I double check it for not to be clogged. It seems that now drain needs "more" air.
Maybe afetr cleaning all things more water volume is in circulation and so more vent air is requiered.
I remember when tank was cycling (about a year) same noise was produced.

Greetings