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FAQs about Bubble Trouble and Aquarium Systems: Pump, Pumping Issues

Related Articles: Plumbing Marine Systems, Plumbing Return Manifolds, Refugiums

Related FAQs: Bubble Troubles 1, Bubble Troubles 2, Bubble Troubles 3, Bubble Troubles 4, Bubble Troubles 5, Bubble Concerns, & FAQs on Causes/Fixes: Diagnosing Sources, Intake/Overflow Issues, Plumbing Issues, Discharge Issues, Biological Issues, & Solved Cases, & Marine Plumbing 1, Marine Plumbing 2, Marine Plumbing 3Marine Plumbing 4, Marine Plumbing 5, Marine Plumbing 6, Plumbing 7, Plumbing 8, Plumbing 9, Plumbing 10, Plumbing 11, Plumbing 12, Plumbing 13, Plumbing 14, Plumbing 15, Plumbing 16, Plumbing 17, Plumbing 18, Holes & Drilling, Durso Standpipes, Overflow Boxes, Plumbing Noise, Make Up Water Systems, Pumps, Plumbing, Circulation, Sumps, RefugiumsMarine Circulation 2, Gear Selection for Circulation, Pump Problems Fish-Only Marine Set-ups, Fish-Only Marine Systems 2, FOWLR/Fish and Invertebrate Systems, Reef Systems, Coldwater Systems, Small Systems, Large SystemsWater Changes Surge Devices

Such air inspiration can be big trouble... leading to livestock losses...

Micro Bubbles Mystery -- 11/18/09
I am experiencing high volume of micro bubbles being ejected into the tank causing a fuzzy/hazy appearance in the tank. I can confirm that the skimmer, calcium reactor, chiller returns, anything else in the sump are not causing the problem because I turned them all off for a few minutes...ran only the return (GenX pump 1500gph) and still seeing bubbles, no micro bubbles are entering the intake bulkhead to the pump, only coming out the returns in the tank.
How is this possible?
<<It would seem that air is being drawn-in somewhere along the pump return line>>
Have things grown on the impeller of the pump to act as a needle wheel?
<<Not likely to such an extent'¦and would still need some type of air infusion>>
Is that a possibility?
<<An unlikely one'¦though cleaning the pump's impeller and volute can't hurt, and will likely improve its performance/efficiency>>
Somewhere along the lines of the return lines is the problem,
I'm using a 1" SCWD too, maybe that is chopping up bubbles...not sure...
<<No'¦ The mechanism 'within' the SCWD is not the problem, although the line connections may well be. Try removing the SCWD and see what happens>>
at this point I'm thinking of exchanging the pump for a brand new Pan World instead in hopes of eliminating the problem which has been going on for maybe a month now.
<<This would be a better pump in my opinion, but just exchanging pumps is not likely going to resolve your issue here. You need to check 'every' joint/fitting along the return line for a possible air leak (and it probably won't be visible re any leaking water). Utilizing something like a silicon grease to smear-on and seal the joints will help. Do this, one joint at a time, until you find the culprit'¦and then make your repair. Or simply rebuild/replace the entire pump return line if not to extensive a project>>
Thanks for your input,
<Happy to share'¦ EricR>>

Re: Micro Bubbles  11/18/09
Yeah i think we're on the same page here. The air must be coming in somewhere along the return line connections. I was looking for any signs of salt creep that might indicate a bad connection. but these bubbles are soo small that they are being "sucked" in along the lines from a tiny tiny hole somewhere, probably wouldn't be any salt creep because the inside pressure would not allow it to leak out but only draw in small air instead im thinking. Guess I have some tinkering around to do. Will try the replacement pump first since i need a backup anyway and this Genex is pretty noisy, then mess around with connections.
Thanks for your response.
<Mmm. Do read re others adventures with these sorts of issues: http://wetwebmedia.com/bubtroubfaq2.htm
and the first linked file in the series above. Someone here placed your resp./query in my in-folder, but am going to send to EricR for his input as well. Bob Fenner>

Re: Micro Bubbles Mystery -- 11/21/09 (Eric's go)
Yeah I think we're on the same page here. The air must be coming in somewhere along the return line connections.
<<Is often the case (see WWM re)>>
I was looking for any signs of salt creep that might indicate a bad connection but these bubbles are so small that they are being "sucked" in along the lines from a tiny tiny hole somewhere, probably wouldn't be any salt creep because the inside pressure would not allow it to leak out but only draw in small air instead I'm thinking.
<<Yes'¦such small leaks are very often visually undetectable>>
Guess I have some tinkering around to do. Will try the replacement pump first since I need a backup anyway and this Gen-X is pretty noisy,
<<A good place to start>>
and then mess around with connections.
Thanks for your response.
<<Happy to share'¦ EricR>>
<Mmm. Do read re others adventures with these sorts of issues: http://wetwebmedia.com/bubtroubfaq2.htm
and the first linked file in the series above. Someone here placed your resp./query in my in-folder, but am going to send to EricR for his input as well. Bob Fenner>
<<Thanks Bob'¦and my apologies to you and Martin for the delay in my response. A family emergency has resulted in a hectic couple of days>>
<No worries Eric. First things first. I hope/trust all is well now. BobF>

R2: Micro Bubbles Mystery -- 11/21/09
Hey Eric,
<<Hey Mathew'¦and sorry mate, I just realized I referred to you as 'Martin' in my last response>>
The problem was the pump. I switched it out with an older spare pump GenX 1140gph. Surprisingly the older pump was quieter and moved practically the same amount of water.
<<Ahh'¦is likely 'cleaner' too!>>
Apparently the GenX 1500gph pump had accumulated so much dust buildup on the fan cover and pump itself that it basically became so hot you couldn't even touch it without burning yourself.
<<Indeed'¦ These pumps are not 'install and forget' pieces of equipment. Twice annual cleaning'¦inside and out'¦is always recommended, regardless of how the pump is performing>>
That had to have been related to the micro bubble problem somehow because after the switch, no more micro's.
<<So it would seem, yes>>
Always a good thing to keep your main pump clean and in good condition or heat problems can occur and oddly enough, micro bubbles.
Guess this proves that there were no problems with the return line anywhere or SCWD.
<<Always good>>
<<I'm glad you were able to resolve the issue so quickly and easily. Cheers, Eric Russell>>

Bubbles in Main Tank, cavitation? 1/13/07 <Ken, Graham T. with you tonight.> I have a 180 gallon tank plumbed into the basement which dumps into a 300 gallon sump. <Big sump. Good.> The return line is 2" pvc to a hammerhead pump which pumps a head of about 12' in 1.5" pvc to the tank. I am circulating about 3,500 gallons per hour from the sump. <I only see one hammerhead pump with a 2"inlet and 1.5" outlet, and it isn't rated for that head... but I probably missed the one you have.> I also have a closed loop moving additional water within the tank with four returns. My issue is that I am having tiny bubbles returning from the sump to the main tank. The sump is very calm , tiny bubbles not visible and I have tried a return box with sponges to trap possible bubbles and multiple inlets to decrease the intake draw of water, nothing seems to decrease the bubbles. Can my powerful pump be chopping the water and creating air bubbles. <That would be my guess. The large differences in pressure associated with pumping volume at that head with induce cavitation. Cavitation, simply put, is just water boiling because of the extreme low-pressure on the input side of your pump. Remember, it is not just heat that makes water boil, but pressure differential. Adding more lines to feed the tank will do little or nothing since the low pressure is found at the impeller-housing, after the 2" restriction. The real change must be made at the out-put stage. Unfortunately, if you do have the pump I spec'ed out (Dart), then you may be undersized to boot. Either way, utilizing a low-speed pump, using multiple pumps, or enlarging the inlet-size of your current pump are all ways to reduce the unsightly bubbles you generate. HTH, -Graham T.> Thanks Ken

Air Bubbles Hi Bob, I wrote to you earlier about pressure I was getting from a new Iwaki pump I installed on my 300 gallon reef tank. That problem was solved. Here is the latest one: It pumps out a copious amount of fine bubbles into the tank.  <A very bad situation... as you might know... Please read here: http://www.wetwebmedia.com/bbldisease.htm and the accompanying FAQs file> I checked your FAQs and only found some passing comments about baffling. The sump does have bubbles in it from the wet-dry returns, skimmer return, etc. etc. So, what exactly is baffling? Using glass-glass to separate the pump intake from the bubbles? How would you recommend setting that up? <Better to arrange some open cell polyurethane foam intake area (large as possible, two or more layers better than just one large one... to exclude the bubbles) as your sump is not likely large enough to configure a baffling system that would work... with such a large/flow rate pump... Bob Fenner> Thanks, Dale M.

Re: Air Bubbles Thanks so much for the input, Bob. Now, here's the stupid question: What is "open cell polyurethane foam ," and where do I find it? Thanks again! Dale. <Mmm, usually that real spongy yellow foam you see about in "blocks"... that and "batting material" (Dacron polyester) sold in various fashions as aquarium filter matter can be bought for little money at yardage and crafts stores. Bob Fenner>

Re: Air Bubbles OK, I know exactly what you're talking about. In fact, being a collect-a-holic, I have a bunch of it in my garage. I'll wash it out and give it a try. Now, tell me, do I just put these blocks around the pump intake in the sump?  <Mmm, no... need to fashion a sort of "support"... a "cage" of more solid material to support the "foam area" above and away from the pump intake...> You said two or more layers are better than just one. Do I just stack this stuff out, up, and over the intake? <Stacked yes... but as I state, a few inches from the actual intake... so as it gets a bit clogged, it doesn't get sucked in, restrict the inflow> You are a god-send. Sometimes, these aquarium issues get mind boggling. <One of the reasons, properties we enjoy... Bob Fenner> Thanks! Dale.

Bubbles in tank--plumbing question >Hey there, >>Hey there yourself, fella. ;)  Marina tonight. >I have a question for you. >>A'ight. >I recently turned my 125g fresh water tank over to a mixed reef which is to be stocked with the contents of my 75g. with the new tank I wanted to use a sump based filter system so I got a bs2 sump with a CPR cs102 overflow. I don't seem to have problems with bubbles from the over flow I think because of the media bags included with the bs2 but I am getting bubbles in the main tank from the return pump. I use an Iwaki Welshman wmd40rlxt this pump is rated at 1200 gph with 1" in and out. The overflow is supposed to be 1400gph but the return pump is draining water too fast from the sump which creates a funnel in the water and sucks air into the pump. I have a valve between the sump and the pump but I think its not the right kind because if I turn the valve the pump seems to suck harder and drains the sump faster. >>Do you know if you're using a gate valve (the correct type to use to adjust flow) or a ball valve (best when using at quick disconnect points)?  I suggest using a gate valve. >right know I am using vice grips on the return tubing to slow the rate which works but there has got to be a better way. >>Agreed! >I've been reading the other posts and it seems that most have split the return into two which seems to be a good idea that way I can get some more circulation to the tank. >>Again, yes, agreed, it diffuses the flow, as well as allowing more of the tank to receive freshly filtered water. >I haven't added sand yet but with the return the way it is the sand would be all over with the force that the return is at currently. would the split in the return tubing slow the water so I don't have to use vice grips? and should I be using 1" tubing? I have a friend that thinks the bubbles are from my protein skimmer. >>It's hard to say whether it's the skimmer or the pump (a picture would help), but it does sound as though you've got cavitation happening within the overflow, that pump must really be kickin' butt! >I use AquaC ev180 w/ dolphin dp-800. I also have a Korallin ca reactor injecting effluent into the skimmer. some other considerations I have is that I have the pump connected directly to the bulkhead on the wall of the sump. I was thinking that if I ran something between the two would it quiet it down some? >>A short bit of flexible tubing, perhaps?  It *might* help, but I can't guarantee it.  I'm going to point you to http://www.reefs.org you'll have to register to post, but there are many there who can help as well.  In my opinion it seems you need to adjust the flow going into the pump just a bit, and a gate valve would help you do this.  If your friend is familiar with plumbing setups like yours, and, since he can actually look at it, he feels the issue may be with the skimmer, go ahead and pick his brain as well.  Does the water coming out of the skimmer seem to be holding bubbles in it?  If that's a problem one way to tackle it is to simply let the water from the skimmer fall into the sump, instead being part of a closed loop.  Again, without seeing how you have this set up it's bit tricky to offer definitive advice. >Thanks for your time any suggestions would help. Scott Ballantyne >>I'm forwarding this message to a couple of others who I think are going to have much better experience than mine, if they have anything to add hopefully they'll email one of us.  I do hope this has helped a bit, and good luck!  Marina

Tiny bubbles Hi WWM crew! This is me from Guatemala, the land of eternal spring! <cheers! Carlos> This is my question. Often the main pump in the sump capture little bubbles originated in the sump due the internal turbulence... when the pump capture this bubbles, the pump brake it in myriads of tiny bubbles that you can see in the main tank... those bubbles can affect in some way the life in my tank? <yes... called "microbubbles" the aspirated air is whisked through the impeller and can cause some problems with animals in the system. Stuck to invertebrates they can be irritating and in rare cases they cause supersaturation of oxygen and a condition like Nitrogen "bends" in divers for the fishes. Prevent the bubbles by installing a baffle of glass before the pump intake or keeping a large coarse foam block on the pump intake (and clean weekly)> Thank you! Carlos Díaz <best regards, Anthony>

Bubbles in a New Set-Up - 9/24/03 Hello Great Wet Web Crew;) <cheers, Joe!> First off, really enjoyed Anthony Calfo's article at reefs.org ( http://www.advancedaquarist.com/issues/sept2003/short.htm) it was especially helpful since I'm setting up a new system with a problem. <good to hear> It's a 75 gal, gallon tank with a built in return box. It's plumbed to a 15 gallon sump with 1.5 inch PVC and returns through an external 970 GPH mag drive pump. <FWIW... the sump is rather small. Going to be tight to work in, and too dynamic to serve as a refugium, settling chamber, etc in the future> Here's the problem, at full flow I'm getting what look like superfine air bubbles from the articulated return. This did not occur when I ran it with only fresh water to test the plumbing once adding the salt (Red Sea) the bubbles popped up. I've siliconed everything in creation from and including the sump connections up to and in including the pump connections. There does not appear to be any to be any bubbles in the flow tube (clear) coming up from the pump. After reading many of the articles and FAQ's on air bubbles I was wondering if it could be that at full power the pump is pulling air into the line from the sump and chopping it up? Some kind of pressure differential? <hmmm... I'm not convinced of that> Could this kind of air be pulled in on the output side of the pump? <yes... much more likely. And surprising to many folks that would expect a pinhole leak to spray water (which it rarely does) rather than aspirate it like a venturi (you guessed it!)> Anyway your thoughts would be helpful before I pull all this plumbing apart. <yes... temporarily disconnect the articulated aspects... or even the entire return structure... from the pump, and run a single hose return up to the tank. Assuming that the single connection off the pump is a good seal... this will tell you if some aspect of the original articulated return has a pinhole leak or not. Take the ball and run with it from there> Could the pump housing itself be pulling air in? <indeed... even the fittings on the inflow side. If not silicones... consider, or test with Vaseline> On another note, in Mr. Calfo's article he mentions his dislike of "reef-ready" tanks which is exactly what I have (Oceanic Systems)!!! <they are a nice thought... but grossly under-plumbed> Any thoughts on improving the return flow in such a system. <yep... short of drilling more holes... use all drilled holes (2 drains and 2 returns) for drains. Then simply return the water up the back/side of the aquarium like described in the manifold article> Sorry to be long winded and thanks in advance for your help. <no worries... our pleasure> Is you new book available in the big book stores yet or only through you? <I believe/hope it has begun to trickle down through the chains of distribution. Amazon.com has it... and I have an extended list of dealers and distributors of our books at readingtrees.com> Thanks and be well, Joe <with hope for you in kind my friend, Anthony>

- Pumping Air - Hello crew, Let me start by thanking you guys for such a great site with tons of info. I am looking to get some additional clarification on a response posted by Anthony to another e-mailer. I am looking to replace the 4 power heads in my 120 gal reef tank with a closed loop system.  The tank is 4x4x2 with 2 corner overflows each having a 1" drain.  I have tried pumping directly from the sump but "surprisingly" the overflows can not handle the additional flow.  I do not have enough courage to drill additional holes. <Is something that should be done when the tank is dry.> I have an extra Mag-drive 9.5 that I was hoping to use as an external pump to power the closed loop.  I wanted to place an intake just below the water line, plumbed to the Mag-drive sitting on a shelf (outside and above the sump to reduce head but below the water level in the tank) then plumbed directly back to the tank.  In reading through the daily FAQ'S I found this exact setup described, which I have attached for reference.  I have tried this setup and I can't get the pump to prime itself or gravity feed up an over the back of the tank without a manual siphon. <I think perhaps you misread Anthony's intent. The inlet for the pump AND THE PUMP must be below the water line. By running the intake line up and over the tank's edge and above the water line, you've essentially put the pump above the water line. There are very few pumps out there that self-prime on a dry line or will suck water up hill.> The pump works fine when it's submerged but won't self prime. <Pumps of this design do not "self-prime" in the typical sense of the word. If they are already full of water, they will move that water, but they will not pull water through a dry line.> I have researched these pumps and the claim is that they can be used in-line or submersed. I am assuming in-line means external. <Yes, but at or below the level of the water... if you had a bulkhead in the back of your tank at or below the water level, this pump would work fine.> In Anthony's response to another reader on this very question he states; "with an inlet sufficiently below the running water line, the pump will be gravity fed and self prime (if kept clean... service quarterly or better) after interruptions of power>".  I am not sure what I am missing. <Putting a hose up and over the edge of a tank is not the same as what Anthony describes.> As long as the intake is below the water level inside the tank why does its elevation matter? Is the elevation of the pump itself critical? <No, it's all about the air in the hose, and the fact that the position of the hose essentially requires the pump to pull the water up hill.> Or can this type of pump just not be used for this application? <This pump will not pull air if that is what you are wondering.> Any help or further clarification would be greatly appreciated as I would love to get rid of the power heads and make use of this spare pump.  Thanks for all help.  You guys are the best. Marty <Cheers, J -- >

Micro Bubbles Dear Crew, <Steve> I'm having problems with micro bubbles. I have a PanWorld 40PX dedicated to a chiller and a sea swirl and I'm not having any problems. I also have a Gen-X Mak4 that is dedicated to 2 sea swirls and that is where I'm having my problems. I have siliconed all connections, placed a sponge in the sump and I'm still getting the micro bubbles. I notice at times that I will get a surge of bubbles that will shoot out both of the sea swirls, could it possibly be the pump? <Yes... you may be able to detect a small air leak... with a length of tubing placed near the pump... and your ear... or a spray bottle of water spritzed about the volute... or simply turn all off, secure the intake, discharge lines, take the volute off, clean and re-lube the 0-ring... and put back together. DO check all flexible connectors on the discharge side up to where the lines enter the water...> This is a new set up and I do not have any corals as of yet. Will this be a problem if the bubbles do not stop? <Possibly... sometimes such problems "solve themselves" (mainly through gentle salt creep)...> Any insight or suggestions would be greatly appreciated. Thanks Steve <Maybe have another aquarist mystery solver come over and look your system over carefully... Good hunting. Bob Fenner>

Air bubbles and fish spots... Hello crew! I just want to say thank you for all the time and support that you and your crew provide to these questions.   I've been looking online for the answers to these questions, but I can't find the answers to my specific questions.   First, I have fine air bubbles returning to my tank clouding the water.  I know, don't say it; I have spent days reading the past FAQ's.  My particular problem is that periodically (every 20 minutes or so), a surge of bubbles enters the tank.  It's like the air is building up in the pump, then it spits it out. <Yikes, not good... can be dangerous to your livestock... there is an intake leak... somewhere... that you should look, listen for and fix... a spray bottle of water, a length of tubing... for spritzing on lines, fittings, the pump volute... and the tubing for listening for intake "hiss"...> I have siliconed all my joints before and after the pump and still microbubbles.  I don't have bubbles entering the sump so it is not coming from there.  I'm really out of ideas as where this air is coming from and how to solve the problem. <With someone helping, try pressurizing the line (blocking the discharge/s...) you may see water seep to shoot out of the intake source... otherwise try wicking a napkin/paper towel along the entire intake line... for water>   I have a 150 gallon with 100 sump below.   Second question is not a problem, I'm just curious if you have seen this before and what it is... At night, I often use the flashlight to see all the different life forms emerging.  I have six green Chromis and when I shine the flashlight on them, they have large 1/8 inch spots on the fish.  During the day, they have no spots and they are healthy.  Disease free for months.  Have you observed this before?  Normal?  Should I be concerned?   Thanks for your input in advance.   Dan <Likely what you observe, describe well here are "nocturnal markings"... changes in the fish themselves that may aid them in the wild in avoiding piscivorous predators. No worries. Bob Fenner>

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