Return pump spitting bubbles (NOT the skimmer or water splashing)

[Bpainter3]

Hey everyone. My return pump is spitting bubbles randomly just a little here and there like it’s sucking air from somewhere. The plumbing is ran up the back of the tank not through the return slot in the over flow. As it says in the title it’s not the skimmer or water splashing I know this for a fact you can see from the pics below I have two sponges in between baffles. I have double checked every pvc connection and have found no leaks. I have also made sure the connection where the loc line is screwed in is underwater to make sure it wasn’t that. I have unscrewed and screwed back together the union. Last I sat there for 15 min and watched to make sure a random bubble wasn’t collecting through the two sponges being released randomly and getting sucked into the return.

Has any one else had this happen could there be a pinhole in the plumbing connections somewhere that’s not leaking but allowing air in? That’s the only thing I can think of. Figured I’d ask before I rip the whole thing apart.

Thanks in advance!

 

[Hypan]

Take another real close look at all your pvc joints for any salt creep.

Sounds like you may have a pinhole in one of your joints

How exactly is your plumbing set up up the back. May have a bubble caught in a joint somewhere

 

[OutsideBrian]

Is that first picture your return chamber? If so why is it so shallow? Might not be your cause but doesn’t look right.

 

[kapnkush608]

Definitely sounds like a leak somewhere in the return line and the water running past is creating a Venturi effect.

 

[Bpainter3]

Take another real close look at all your pvc joints for any salt creep.

Sounds like you may have a pinhole in one of your joints

How exactly is your plumbing set up up the back. May have a bubble caught in a joint somewhere

I have triple checked them I don’t see anything or feel anything it’s been doing it for a month and a half since I set the tank up. I just checked it again no salt creep or moisture on any connections. The right return pump is plumbed the same way and no problems. I have plumbed many other tanks the same way. Maybe it’s the return pump mag 18? I’ve shaken the return line many times as well to work a bubble out of there was one.

Thanks for the response

 

[clm65]

For it to suck in air, the leak would need be on the suction side of the pump (unless you have some sort of venturi on the discharge). Since it looks like your pump is submerged, the suction piping is not likely the problem. What is that bulkhead on the right side of the top picture for? Does something drain into the pump chamber there that may occasionally have entrained air? Your pump inlet is close to that fitting, so it may capture some air if that is the case.

 

[Bpainter3]

Is that first picture your return chamber? If so why is it so shallow? Might not be your cause but doesn’t look right.

Yes it is the return chamber it’s actually higher than recommended haha

 

[Bpainter3]

Definitely sounds like a leak somewhere in the return line and the water running past is creating a Venturi effect.

I wish there was so I knew what was causing it I’m wondering if it’s the return pump. There is no moisture on any part of the plumping I just ran my hands over everything with dry hands

 

[BadFish619]

Just went through this. Ended up being a joint that needed repair. Drove me crazy for 3 days

 

[Bpainter3]

For it to suck in air, the leak would need be on the suction side of the pump (unless you have some sort of venturi on the discharge). Since it looks like your pump is submerged, the suction piping is not likely the problem. What is that bulkhead on the right side of the top picture for? Does something drain into the pump chamber there that may occasionally have entrained air? Your pump inlet is close to that fitting, so it may capture some air if that is the case.

No it’s just connected to my second sump I have sat there and watched for 15 min nothing goes in and I got bubbles two or three times. the only place I can’t really see or touch is the straight pipe going up the back of the tank but I figured there’d be water on the floor by now

 

[Bpainter3]

Just went through this. Ended up being a joint that needed repair. Drove me crazy for 3 days

And you had no leak? Or salt creep?

 

[BadFish619]

Nope. But I had switched a few things in the sump so I had probably knocked it so it was a new thing

 

[BadFish619]

Keep us in the loop!

 

[KorD]

Are you seeing a burst of bubbles, nano bubbles the whole time, or what?
I'm trying to picture what you see..
I know it sounds no fun, but besides glueing my pipes, I also put a thin bead of aquarium caulk on my joints.

 

[Bpainter3]

It’s like a random shot of micros bubbles maybe once every 5 to 10 minutes. I’m thinking about just putting epoxy on each joint one by one to see when I and if it stops

 

[Bpainter3]

Are you seeing a burst of bubbles, nano bubbles the whole time, or what?
I'm trying to picture what you see..
I know it sounds no fun, but besides glueing my pipes, I also put a thin bead of aquarium caulk on my joints.

It’s like a random shot of micros bubbles maybe once every 5 to 10 minutes. I’m thinking about just putting epoxy on each joint one by one to see when I and if it stops

 

[Bpainter3]

Keep us in the loop!

Will do!

 

[KorD]

It’s like a random shot of micros bubbles maybe once every 5 to 10 minutes. I’m thinking about just putting epoxy on each joint one by one to see when I and if it stops

Epoxy is good, but if you ever need to cut it off you will have a hard time. Caulk is the way to go for that.

Also watch your sump.. your skimmer could be throwing nano bubbles you can't really see. They make it easy through the water and sponges into your pump..
I had that problem and had to put a filter over the end of my skimmer and also took my line from the tank to the sump and added 2 90°s to force the water upwards so the bubbles didn't disperse in the water collum anymore.. took me a week to figure it out.. worst part is I have plumed three tanks the same way. This tank was my naughty "I hate you" tank.

 

[Bpainter3]

Epoxy is good, but if you ever need to cut it off you will have a hard time. Caulk is the way to go for that.

Also watch your sump.. your skimmer could be throwing nano bubbles you can't really see. They make it easy through the water and sponges into your pump..
I had that problem and had to put a filter over the end of my skimmer and also took my line from the tank to the sump and added 2 90°s to force the water upwards so the bubbles didn't disperse in the water collum anymore.. took me a week to figure it out.. worst part is I have plumed three tanks the same way. This tank was my naughty "I hate you" tank.

If I have to cut it I’ll just cut al the epoxy parts out and completely replumb it. It’s more just to see it there’s air getting through a connection.

That’s a great idea but I’m 100 percent sure it’s not the skimmer I have two skimmers both barley put out microbubbles and I have two fine sponges in between the baffles. It’s definitely something with the plumbing.

 

[w2inc]

how deep does your return line stick down into your tank? Is there an air hole in it to stop a syphon?