Trying to dial in return flow

SenorCappuccino · Mar 16, 2021

I just had my pump die on me. I went and purchased a Syncra Silent 4.0. My tank is about 120gal w/ sump included. I've been having a lot of issues with gurgling. The pump is dialed all the way down with a ball valve restricting probably 60% closed. Any ideas to silence the overflow? Its a durso set up.

dbowman5 · Mar 16, 2021

if your durso is gurgling with this pump and was not with the previous pump what pump did you have before?
is there more flow or less. when the air hole is the wrong size there can be gurgling check out melevsreef on youtube

Lost in the Sauce · Mar 16, 2021

I just tore down a 120 with durso piping that was quiet when we moved it and LOUD gurgling after setup. I had to drill a 1/4" hole in the very top to break the siohon. Throttling my return pump with a ball valve did nothing. Immediately started flowing correctly with the new air hole.

landlubber · Mar 16, 2021

i also have a durso and they can be finicky depending how long the stack is that the water flows through to get down to the sump, how long it is into your sump and the size of the hole at the very top is.
the first thing i'd try is to drill out the vent hole at the top. you can also dial this in by installing a piece of RO tubing with an inline valve to throttle it.
durso's require a bit of tweaking to get quiet

SenorCappuccino · Mar 16, 2021

dbowman5 said:
if your durso is gurgling with this pump and was not with the previous pump what pump did you have before?
is there more flow or less. when the air hole is the wrong size there can be gurgling check out melevsreef on youtube

I had the Eheim compact+ 3000. Thats the pump that came with my tank and also had a gurgling issue with that.

stanleo · Mar 16, 2021

My overflow gurgles loudly as well. I have tried getting used to it. I tried everything. Some days I don't notice the sound, some days it drives me batty.

dbowman5 · Mar 16, 2021

my bean animal gurgles on start up while the siphon is establishing if there is not enough water flow to cover the intake like when i am dialed down for feeding the noise is bad!! as soon as i ramp up to normal flow the sound goes away. if you are using a durso the intake should be under water at all times and there should be no vortex. if there is then the air hole is too small and you are sucking air with siphoning. if the flow is too slow then there is an open pipe and you hear water falling depending on small variations the noise you hear can be different on different days. what kind of overflow box are you using?

SenorCappuccino · Mar 16, 2021

dbowman5 said:
my bean animal gurgles on start up while the siphon is establishing if there is not enough water flow to cover the intake like when i am dialed down for feeding the noise is bad!! as soon as i ramp up to normal flow the sound goes away. if you are using a durso the intake should be under water at all times and there should be no vortex. if there is then the air hole is too small and you are sucking air with siphoning. if the flow is too slow then there is an open pipe and you hear water falling depending on small variations the noise you hear can be different on different days. what kind of overflow box are you using?

So this tank was purchased used. This is what the previous owners did to the pipe. Could this be the problem?

dbowman5 · Mar 16, 2021

SenorCappuccino said:
So this tank was purchased used. This is what the previous owners did to the pipe. Could this be the problem?

yes, when i look at this pic i see two pipes. if they are both drains is there water going into the one on the right?

SenorCappuccino · Mar 16, 2021

dbowman5 said:
yes, when i look at this pic i see two pipes. if they are both drains is there water going into the one on the right?

So the one one the left side is the actual pipe leading to the sump. You can't see it but the right side is attached to the nozzles going into the display

dbowman5 · Mar 16, 2021

SenorCappuccino said:
So the one one the left side is the actual pipe leading to the sump. You can't see it but the right side is attached to the nozzles going into the display

thanks, the holes in the elbow regulate the amount of suction on the inlet. ideally the water level would be somewhere below the top of the inside of the horizontal portion of the elbow. the hose stuck into the one hole would allow air to keep full siphon from developing even if the whole elbow was submerged. that can happen with flow changes. since you have tried cutting the return flow down have you tried maintaining a higher flow? or stopping up one or two of the holes?

SenorCappuccino · Mar 16, 2021

dbowman5 said:
thanks, the holes in the elbow regulate the amount of suction on the inlet. ideally the water level would be somewhere below the top of the inside of the horizontal portion of the elbow. the hose stuck into the one hole would allow air to keep full siphon from developing even if the whole elbow was submerged. that can happen with flow changes. since you have tried cutting the return flow down have you tried maintaining a higher flow? or stopping up one or two of the holes?

Just tried stopping up a different combo of the holes as well as adjusting the flow with no difference.

dbowman5 · Mar 16, 2021

is there a valve on the drain? there is not usually one on a durso but the question in my mind is whether the noise is caused by water falling or by the suction; the difference of a straw at the bottom of the glass when you noisily suck a combination of air and liquid or the sound of water and air falling together under gravity where the air is fighting to get back up through the water.

dbowman5 · Mar 16, 2021

can you limit the outflow to the sump temporarily to see if that affects the noise level? without overflowing the DT lol

SenorCappuccino · Mar 16, 2021

dbowman5 said:
can you limit the outflow to the sump temporarily to see if that affects the noise level? without overflowing the DT lol

Gave that a shot. I ended up just trying to clamp down the flexible tubing a little and it seems to have slightly improved for the time I was restricting it. Do you think a ball valve to limit the overflow is what i'd need?

Straight down pipe is the overflow. Long across w/ ball valve is the return.

dbowman5 · Mar 16, 2021

SenorCappuccino said:
Just tried stopping up a different combo of the holes as well as adjusting the flow with no difference.

SenorCappuccino said:
Gave that a shot. I ended up just trying to clamp down the flexible tubing a little and it seems to have slightly improved for the time I was restricting it. Do you think a ball valve to limit the overflow is what i'd need?

Straight down pipe is the overflow. Long across w/ ball valve is the return.

i would try it. if the problem is waterfall you would be reducing the distance it falls because the hose would be fuller with water. if it is slurping the flow would be slower allowing the flow to be all liquid instead of so much air. try searching for durso tweaks.