Blueline Pump And Micro Bubbles

[farbeyonddriven77]

Hello Again,

Recently we purchased a blueline pump for a new 240 gallon tank.
After it has all been plumbed and we put fresh water in it to test it out, we have to turn it half way down to get rid of the micro bubbles it's putting out. Has anyone else had this experience? Is there any other way to get rid of the bubbles? We had it figured on turning the tank over 7 times per hour, and now it's only down to about 3.5. Thanks in advance for all of your help.

[newkie]

Its most likely not the pump itself unless the impeller casings seal is faulty. More likely is that as you crank up the pump the velocity through you sump is high enough that the bubbles carried down from the overflow aren't disappaiting but being sucked in by the pump with the water. You can add baffles and filtes to help with that, do a search on bubbles and baffles. Otherwise its probably a pinhole leak somewhere in your plumbing. For all fittings use teflon tape. Then start tackling the piece by piece.

[farbeyonddriven77]

We've got a CPR 3000, and the trickle is seperate from the sump. This was my first thought as well, but there are no bubbles getting into the pump VIA the sump. As far as the plumbing goes, there are absolutely no leaks. After glueing the joints, rather than using teflon tape, we used the self adhesive black rubbery tape, I forget what it's called. Anyways, we used that stuff just to make sure. I don't think that it's the impeller housing, wouldn't it still put out bubbles no matter what? It's a brand new pump. Not to say there couldn't be a defect. Is ther anything else it could be?

[farbeyonddriven77]

^

[David Grigor]

I don't own a blueline but am 99.99% sure it's not the pump.

As long as your sure bubble are not coming from the sump. It has to be pulling air in from one of the joints in your return line somewhere............because it is pulling air into the return line your not going to visably see or be able to tell that it's actually leaking.

First thing I would do is try to simplify the plumbing as much as possible by removing as many uncessary joints etc.

[farbeyonddriven77]

first of all, thanks for your reply. As far as leaks, we left the pump off and let the water stand in the plumbing for two days , and couldn't find any drips or drops anywhere. Is it possible that the pump just may be too powerful, and is going so fast that it's seperating some of the oxygen from the water by centrifugal force? It just sucks cuz we spent the money on trying to get the right amount of flow for about 7 times per hour turnover, but at half , we could have probably spent a lot less on a smaller pump, and not be putting so much strain on it. The plumbing is as simple as we can get it, without taking out necessary pieces of the setup.

[newkie]

What we're both trying to tell you is that you might not see any water leaking from your plumbing but that doesn't mean there isn't a pinhole leak that is sucking air like a venturi. So before you give up try this: bypass as much plumbing as you can. I.E. for the return get a 3/4" nipple and some flexible hose and just clamp it over the side for testing. For the intake be equally creative. Just break it down piece by piece. Also, like I said, it could be a bad o-ring in the pump. Try opening the impeller casing up, give it a rinse in case there is some grit in there, then close it back up.

[David Grigor]

Originally posted by farbeyonddriven77
first of all, thanks for your reply. As far as leaks, we left the pump off and let the water stand in the plumbing for two days , and couldn't find any drips or drops anywhere.

It's is doubtfull that you would find the leaks this way because there is no real pressure.

I bet that if your were to close off all the ends on the return line ( or severly restrict them ) then turn the pump on that would create enough pressure in the return line that you would then see water dripping from the joints where the air is getting into.

[farbeyonddriven77]

that's a damn good idea, but that won't create pressure in the plumbing before the pump will it? I think that if there is a leak, it would be before the pump because of the size of the bubbles exiting the returns. I will however try this idea, to see if there are any leaks after the pump.

[David Grigor]

Definately want to restrict AFTER the pump. So restrict the outlets /nozzles that are in the tank where your seeing the bubbles coming out. Not before as that would harm the pump.

Your wanting the pump to basically build up pressure in your return line to help identify the leak....

[farbeyonddriven77]

I think that if there is a leak, it would be before the pump because of the size of the bubbles exiting the returns. Also, I forgot to mention, you can hear the bubbles going through the pump. Man, it sounds like a lot of work tocheck the seal on the housing, hopefully, it doesn't come to that.

[Vert20]

What size is your pump inlet?

You say when you throttle it back (less volume) that the bubbles go away...sounds like the impellar is cavitating and causing the bubbles.

Just my opinion...

[farbeyonddriven77]

Vert20, yeah, this is what I was thinking, would that mean that it's just a poorly designed pump? both the inlet and outlet are 1" MPT

[Vert20]

It sounds like the inlet may be restricted somehow. I am not saying they are poorly designed pumps. I have never owned one. I am just offering up suggestions...sry I could not be more help

[farbeyonddriven77]

The only restriction there is on the inlet is a 90 pointing down into the sump to keep the pump from drawing air from the water's surface. we have tried all different levels in the sump, all the way up to full, and there are still microbubbles, no matter what.

[in2deep]

"After glueing the joints, rather than using teflon tape, we used the self adhesive black rubbery tape, I forget what it's called". I don't know much about plumbing but the black duct tape stuff sounds questionable at best. It sounds like you are suffering from the "Gore-Tex syndrome"- Air is able to be sucked in at the joints but the leak is too small to pass water thru. I think i heard about this from an old Seinfeld episode so take it with a grain of salt.

[farbeyonddriven77]

Yeah, it's not duct tape though. It's designed for sealing plumbing joints. It's really cool stuff, and completely conforms to the joints.

[SPC]

After glueing the joints, rather than using teflon tape, we used the self adhesive black rubbery tape, I forget what it's called.

But you do understand that teflon tape is not made for this purpose don't you? I mean, why do you think you would need teflon tape after you have glued the pipe?
Steve

[farbeyonddriven77]

Originally posted by SPC
[b]After glueing the joints, RATHER than using teflon tape, we used the self adhesive black rubbery tape, I forget what it's called
We didn't use teflon tape. Besides, you don't use teflon tape on glued joints anyways do you?

[chewie]

What size bulkhead is feeding your pump? If it is smaller than a 1" bulkhead then that is your problem. Other than that I don't know.

Besides, you don't use teflon tape on glued joints anyways do you?

Nope! You use teflon tape on threaded fittings only.

I do know about the black rubber tape used to seal leaky drains.

Basically you're saying that you wrapped it around the joints after glueing right?

[farbeyonddriven77]

yes, that's correct, we glued, then wrapped. I belive that it is a 3/4 inch bulkhead. You think that this is the problem? We did use teflon tape on the threaded parts. I pretty much knew that you don't use it on the glue fittings, I just didn't know if there was some secret to using it on glued joints as well.

[Rockfish]

Vert20,

Just went through this with my pump. I was getting micro-bubbles by the million. My return splits in two to go back in two different areas of the tank and bubbles were spewing from both outputs. This told me it was coming in from the suction side/intake of the pump. Looked in the sump and no bubbles in the pump uptake area of the sump. The problem was I had 8 bags of carbon laying in this area and the pump pulled water through them, some of the bags where exposed to air just barely and the rest of the bag was around the intake. It was using the mesh bag like a tube to pull air in and down through the carbon and into the intake (my hypothesis only). I removed the obstruction (carbon bags) and the bubbles went away. This is my take on how the bubbles got there, unless it just caused cavitation to occur due to not enough water intake to occur. But I do know that removing the bags, led to no more bubbles. Check obstruction for sure. Never restrict input to the pump only output. Output restriction counts as head pressure but is not that detrimental to the pump if within the manufacturers guidelines. If your troubleshooting only change one thing at a time to rule it out of the equation. This way when you do find the problem at least you'll know what it was for certain. Unless of course you have a multitude of problems.

[farbeyonddriven77]

yeah, there's nothing in the way, the sump is empty except for water.

[Rockfish]

A pin hole leak is some where. If it is perfectly calm in your sump area, get a piece of incense and light it. Wave it around the joints and if there is any joint not tight and sucking air, it will disrupt the smoke enough to see the area.

[chewie]

Are you the same dude who posted this http://archive.reefcentral.com/forums/showthread.php?s=&threadid=193814 a few days ago?

Reducing the inlet will cause cavitation. Your pump has a 1" inlet and it needs to be hooked up to a 1" bulkhead. If it were me I'd go 1.5"

[farbeyonddriven77]

I'm starting to think that this may be the case, and will probably try to change it out this weekend. No, pantera4203 is the other cat in my office. We have been working on this tank together.

[newkie]

Originally posted by chewie
Your pump has a 1" inlet and it needs to be hooked up to a 1" bulkhead. If it were me I'd go 1.5"

Actually the Blueline1100 has a 3/4" inlet/outlet

[farbeyonddriven77]

NO, it's a blueline HD100.

[Puffer Daddy]

Hey partner...not to be saying the same thing you've been hearing but I had the same prob..mine was cross threaded teflon which allowed the air to be pulled in. I was absolutley amazed on how small a hole had to be for this to happen..oh, and mine didn't leak. Got lucky and found it..Fixed it and it happened again. This time, I had overtightened a 90 fitting from the pump..created a very, very, very small hairline crack..Newkie and the others are right..Im pretty sure this is were your problem is..Good luck, I know it can be frustrating.

[farbeyonddriven77]

Yeah, I think that I'll go over it again, just to make double sure. Man, I hope I find it.

[SPC]

Originally posted by farbeyonddriven77
We didn't use teflon tape. Besides, you don't use teflon tape on glued joints anyways do you?

No, you sure don't. It just seemed to me the way you worded this: After glueing the joints, rather than using teflon tape, we used the self adhesive black rubbery tape, I forget what it's called., but I see now that you meant you glued instead of using teflon tape?

Let me ask another question, did you use glue in the threaded connections?
Steve

[farbeyonddriven77]

No, we used tef tape. None of this stuff was cross threaded or anything.