Help! Micro Bubbles in Closed Loop?

[Poseidon's Vortex]

I'm getting some bubbles in my closed loop and im not sure what is causing it, i checked all my glue joints and taped over them incase some air was sucking in, and checked the tubing connectors to the pump housing.. all is tight..and there are no water or air leaks that I can detect.. I also shut down my return from the sump to make sure the skimmer wasnt pushing in MB into the tank and the CL just pushing them around.

I think It might be caused by the way my intake to the pump is setup and im looiking for input and feedback from anyone about this. I have heard sometimes it takes awhile for the lines to get slimed for this to go away, my tank has been up about a week now..? Could this be the cause? The bubbles arent massive but noticable.

I dont know if thats enough time I think it would be, but If I have to make changes to fix this I would rather do it when only the rock is i n it.. and I plan on adding fish this weekend if all goes well with testing this saturday.

Without a drawing this would be tough to explain so this is what my current setup looks like feeding my P4 Poseidon 1250 pump..My closed loop is plumbed all the way around with 1" PVC a few unions and reduced at the tank with 3/4" Bushings which the 3/4" LocLine screws into.

I originally didnt plan on doing a closed loop but had pre drilled the two holes in my tank about a year ago for the internal overflow, BEFORE I decided on a HIBO, (hang IN BACK overflow)which eliminated the need for the two BHs.. I decided to use them vs cover them. One is for the sump return the other is for the pump intake.. The pump intake is 1"

The way my tank is setup is that the pump sits level behind the tank on a shelf even with the bottom of the tank and is fed by the return coming through the BOTTOM of the tank..

This is what it looks like from the back (before painting the PVC BLACK)

After painting the PVC with special plastic spray paint (aversion to white pvc around black tank)

I use this picture just to show the pump location in relation to the tank.. My current setup I cutout the CROSS fitting in the above pic going up to the upper level 3/4" returns since the pump couldnt handle all that head and flow, because it acted like a venturi pulling in water from the lower 1" rack (since it reduced at the top part of the cross down from 1" -3/4") it pulled in from the sides. Another problem was the majority of the flow went up to the 3/4" (path of least resitance from the cross) which is something else i didnt want..

Right now I just have the lower 1" section hooked up to the pump with one T fitting. After painting it with special plastic spray paint ( i have aversion to white PVC around black tanks )

These machinations below help bring in the water from the tank up to the shelf and pump..

you can see the weird J made out of PVC 90s... I have a theory that all those hard turns might be causing turbulence before the intake of the pump and or restricting the pumps ability to easily supply itself with water... =cavation= MB?


One Idea I just had was maybe add a sweeping 90 vs these PVC 90 to reduce head and restriction and maybe this would help reduce turbulence before the water hits the pump, if that is whats causing the MB? Im not sure what to do at this point since removing this intake means draining the tank since the valve is AFTER these 90s.. I would have to cut the PVC apart and install a new 1" and sweeper..

My second Idea which would still require a quick tank drain is to add a LARGER 1.5" intake and put it Horizontal out the back WALL of the tank, just above the sand line inside and above the shelf line of the tank on the outside. Here is what that would look like..

I thought by increasing the intake size it might help supply the pump with more than enough water, and raising the intake to the same level as the pump by coming out the back reduces the need for the J trap below the tank.. I would have to reduce the 1.5" ABS down to a 1" PVC nipple with Barbed hose connector to connect to the P4, since the P4 has 1" HOSE barb.

Here is a shot of the 1.5 OD Using ABS reduced down to 1" PVC and Hose barb

Any opinions are greatly appreciated.. If you want to see a Tank Journal I started from day one.. click the link below. There are lots of DIY tips and ideas in it!

http://reefcentral.com/forums/showthread.php?s=&threadid=474461&perpage=25&pagenumber=1

TIA

 

[MarkM3]

My solution was to smear silicone on the outside of the intake portion of the plumbing to seal any "microscopic" air holes. Keep in mind that it is possible to have a hole so small that water will not leak out, but air may pass through under a vacuum(and since the intake is definately "sucking" it qualifies for a vacuum.)

Nice setup!

 

[Poseidon's Vortex]

good idea ill try that next...seems like its getting worse.

do you think the intake side of the CL PVC plumbing before the pump would be the place to focus on?

Also if somehow its leaking on the hose connectors to the pump.. that could be a challenge to seal since they dont leave much room esp when you have a worm band on there.. you cant even see the end of the tubing to seal it.. One bad thing about the P4 is the housing has 1" Barbed on it. blah for PVC not bad for using tubing all around I guess

I guess water flowing in any portion of the line could pull air in..and add it.. but I like the idea of clear silicone.. Ill try that next BEFORE drilling for the new intake.

Also im toying with the idea to just run some tubing into the tank bypassing that PVC J line below to see how that does.. then I can eliminate THAT as the problem..

 

[Poseidon's Vortex]

welp tried it no go... caulked everything I could see and some stuff i couldnt... Im pretty meticulous when it comes to pvc gluing so I doubt that one of my glue joints is leaking. I looked close and caulked all threaded ones, but they were teflon taped too

Im stumped.. gut tells me I need a new larger intake config.

Ima try bypassing the current intake and going into the tank with a section of 1" tubing to see if its the J in the PVC causing it.. if it is ill prob re drill for the new 1.5" instead of messing with that one.

 

[dnjan]

I would guess that the intake restrictions are causing enough of a vaccum in the pump to cause disolved gasses to come out of solution (not exactly cavitation).

It doesn't look like you have a valve on the return side of the pump, do you? (if not, you should, just so you can remove the pump for cleaning without draining the tank down to the level of the closed-loop return)

If you do have a valve on the return side, try closing it a bit. This will reduce the vaccuum from the pump, and therefore reduce the amount of gas coming out solution due to the vaccum.

If that works, you need to either put up with reduced flow, or re-plumb the intake (larger!) to reduce the vaccum. One other thing you could try - move the pump to the floor. You will now have greater water pressure at the pump, and this might be enough to prevent the gas from coming out of solution.

 

[Poseidon's Vortex]

I would guess that the intake restrictions are causing enough of a vaccum in the pump to cause disolved gasses to come out of solution (not exactly cavitation).

When you say "restrictions" you are referring to the 90s and the "J" formation correct ahead of the pump? The intake is 1" now...should it be larger as a general rule? I see that around on posts was just wondering.

The restriction can cause the PUMP to pull dissolved gases out of the water? jeez.. So all those fittings before the pump along with trying to pull it UP and around the back would help restrict the pump right? So getting rid of that and increasing size could only be benificial? I can do it, I just want to make sure its worth it.

It doesn't look like you have a valve on the return side of the pump, do you? (if not, you should, just so you can remove the pump for cleaning without draining the tank down to the level of the closed-loop return)

Yes I have shutoff valve (not pictured) before the pump and i also have to unions above and before the pump for easy removal..

If you do have a valve on the return side, try closing it a bit. This will reduce the vaccuum from the pump, and therefore reduce the amount of gas coming out solution due to the vaccum.

I tried closing the valve a bit to restrict the flow, but no go

If that works, you need to either put up with reduced flow, or re-plumb the intake (larger!) to reduce the vaccum. One other thing you could try - move the pump to the floor. You will now have greater water pressure at the pump, and this might be enough to prevent the gas from coming out of solution.

Im going to try and bypass the J trap by plumbing the intake for a few minutes just using 1" tubing directly into the tank. I think the turbulence in that J fitting is causing the MB.. just my gut feelings.. if it is, I will then re drill for the larger intake and get rid of the J trap altogether.

Thanks for the reply Ill keep you posted what happens

 

[dnjan]

You need valves on both sides of the pump, and the one I suggested closing is the one that comes after the pump. Partially closing a valve before the pump only makes things worse (in terms of vaccum). Lacking a valve after the pump, you could try partially-restricting the outlet flow, and see if that stops the bubbles.

There are really only two ways to get bubbles - ether a small leak before the pump (and the pump is sucking a bit of air), or knocking disolved gas out of solution with a vaccum. Sounds like you have already tried sealing everything up to prevent the air intake, so it must be gas coming out of solution.

And yes, those elbo's, etc. before the pump are restrictions which increase the vaccum in the pump. Turbulence causes localized low-pressures, so that could be the culprit. As a general rule, it is a good idea to have the pump intake be at least one pipe size larger than the pump outflow.

Best of luck!

 

[Poseidon's Vortex]

mmm thanks for that pump intake Rule of Thumb... thats good to know...

Valves...oh i have valves on each return after the pump i tried throttling those down too but no go (not that that is an option, last thing i want is LESS Flow).. next stop is OSH to get some 1" tubing and see what happens when I bypass.. the J,

If it works Ill re drill for larger..Do you think the larger will cause the pump to work less hard, since there is less 90s and raises before it? That is if i put the new return in and its basically level with the pump as pictured above for the 1.5?

 

[dnjan]

Getting rid of those elbo's will definitely reduce the strain on the pump (and increase your flow!).

Happy plumbing!

 

[Poseidon's Vortex]

also the tank has been up about a week the closed loop about 4 days, should the slime coat be sufficient by now for that NOT to be the problem? I hear sometimes they need to get slimed like skimmers chamber before they stop bubbling... it may be as simple as that, but I doubt it!

 

[KevinM]

First, let me just say, that's a beautiful setup! Very clean, and streamlined looking.

I do see one thing that's going to cause you some problems down the road, though. I couldn't help but notice that you provided no means to isolate the CL pump from the tank. As dnjan said above, you have unions, but no valves. From the looks of it, when it comes time to service the pump, you'll have to drain the tank. It should be in the order of valve-union-pump-union-valve.

Since the tank is only 4 days up, if it were mine, I'd drain it add the valves. Sure, it's going to mean you have to re-do the plumbing, but it's a small price to pay compared to waiting until the tank is fully stocked.

HTH,
Kev

 

[Poseidon's Vortex]

no that picture is old.. the setup is different now. All the returns have individual shutoffs before each 90 where they turn to the tank, Ill take a shot of the new plumbing..setup, I just wanted people to see how the PUMP was connected and going up and back to the shelf behind the tank.. I have changed the setup fairly dramatically since that picture.. Also, even though the top two were not valved, I used plugs in the threaded bh to seal them, so I didnt have to drain the tank... when cutting them off.

HOwever I did have to drain the tank to upgrade my pumps intake and change it to version 2 in the picture above using 1.5" ABS ... I also dumped a 1" BH that was used for the first return and plugged that for future use for something...Now it seems to be working better with not as MANY MB... but I cant tell if it stopped the MB problem for a few days until these new 1.5" intake pipes break in..

In fact I think Ive been toying with the idea to dump the pvc altogether, possibly if the MB continue, and go with 1" braided tubing if i can find it... I think that would increase flow even more to the returns since there MIGHT be less restrictions going to the returns.

anyone know where I can get 1" ID Braided tubing?

If I go with BT, I will probably use Y fitting and split the tubing left and right....with valves just before the PVC 90s on each return..Plugs work nicely tho with no problems until the top two are valved again... I think tubing would give a lot of options as far as pump placement, and I could also get rid of the two unions im using now for the pump, which could also be leaking air into the CL. I could just remove the pump via the Y fitting if needed.

I disconnected the top row of 3/4" PVC and will power that with a DP 650 alone, the P4 couldnt power them and the side 1"s very well if at all. I want good flow from the sides esp since Im prob going to have SPS in this tank, at least that my hope, thats why I want CL with LOTS of clean flow.

 

[Hef]

Just letting you know what I've gone through with Bubbles in Closed Loop.
First off whats been said about how bubbles can enter - pin hole in inlet side of plumbing or air coming out of suspension - is basically correct. Keep in mind that air can come in on the output side also. Not as likely but it can happen, and the way your water all enters the tank, below water surface is the best way to stop that.
Tell me something. What does it look like when the bubbles enter the tank. What I mean, is does a lot of air enter at one time in a big "rush". Or does it randomly just flow in with the water? The big rush comes from air building up in the pump, when it reaches a certain amount it all comes out in one shot. The random bubbles would come from being sucked in to the line on the output side or being cycloned down from the top surface of your water.
I seem to have a problem with my Ampmaster 3000. I'm pretty sure it's drawing air into the pump somehow. Everytime I take it apart it runs fine for a couple weeks, then the air starts. I dont have the suspicions you have with plumbing, I'm running 1-1/2" plumbing directly to the pump. I get the bursts of air every few minutes. I hate it.

Good luck, I'll be watching.
Hef

 

[Poseidon's Vortex]

Well Im happy to report that increasing the intake to 1.5" as mentioned above, and getting rid of the "J trap" really seemed to help. The MB are down to almost ZERO now...There are still some residuals, but I think these will dissipate after the lines break in.

If these small pesky ones continue I will probably get rid fo the PVC and go with Braided 1" assuming there is something wrong with the the lines AFTER the pumps intake,(what about the UNIONS? they dont seem like they would be completely air tight, even when cranked down, but who knows?) because this time I know whats before the pump is pretty solid and sealed VERY Well.

I drained the tank last night (which wasnt as bad as I thought of course only rock in it at this point) and drilled out the hole for the new larger intake. I also replaced the other 1" intake BH with a new one and got rid of the J altogether from my system. For some reason (sand?) the plastic NUT on that BH was a pain to remove..

I didnt have enough PVC in that one anyway to add or subtract anything without totally removing it from the tank. The new one has a good sized little nipple that will NEVER be glued to anything but a threaded fitting, so that whatever gets put on THAT one can be removed or moved.. including a shufoff if needed. Right now it's performing no function but I will think of something,.

Bottom line there is still a steady stream of some MB but significantly less, I am hoping with time even these will dissapear, increasing the pumps intake and getting rid of the J trap really seemd to help, I decided on this move also to hopefully extend the life of this pump, because it wont have to work so hard to pull in water as well as pushing it.

 

[Poseidon's Vortex]

Just letting you know what I've gone through with Bubbles in Closed Loop.
First off whats been said about how bubbles can enter - pin hole in inlet side of plumbing or air coming out of suspension - is basically correct. Keep in mind that air can come in on the output side also. Not as likely but it can happen, and the way your water all enters the tank, below water surface is the best way to stop that.
Tell me something. What does it look like when the bubbles enter the tank. What I mean, is does a lot of air enter at one time in a big "rush". Or does it randomly just flow in with the water?

Seems like a consistant flow of them, but the flow has greatly decreased, Im hoping they will go when the lines get "broken in" a bit more since they have only been installed for about a week.

The big rush comes from air building up in the pump, when it reaches a certain amount it all comes out in one shot. The random bubbles would come from being sucked in to the line on the output side or being cycloned down from the top surface of your water.

I seem to have a problem with my Ampmaster 3000. I'm pretty sure it's drawing air into the pump somehow. Everytime I take it apart it runs fine for a couple weeks, then the air starts. I dont have the suspicions you have with plumbing, I'm running 1-1/2" plumbing directly to the pump. I get the bursts of air every few minutes. I hate it.

Mmmm thats interesting, are you treating with CALC? If you are maybe when you clean your impeller you remove some deposits and when you let it build up after awhile it causes the impeller to cavitate due to debris or imbalance? Just a thought.. either way sounds like as it gets a bit dirty your having problems.. I think in my case my lines need somes slime (i hope thats what it is)

Good luck, I'll be watching.
Hef

 

[dnjan]

Instead of the braided hose, go with spaflex. This is flexible (PVC, I think) tubing that can be glued like regular PVC. Either Home Depot or Lowes carries it (or possibly both - I can't remember where I bought mine last time). I have seen it in 1", 1-1/4" and 1-1/2"

The spaflex is white, so it won't grow algae inside.

Sounds like reducing the inlet resistance has mostly solved your problem (which suggests that the primary cause was disolved gas coming out of solution). Congratulations!

 

[Poseidon's Vortex]

Well increasing the intake did solve SOME of the problems, but I was STILL getting MB in the loop. No matter what I tried with that last setup I couldnt find the problem and couldnt completely rid my loop of mbs... So as you can guess was getting tired of the cloud of bubbles in my tank and decided to drastic measures..

So I decided to re-do the intake section pictured above with a more simple setup..I also dumped the shutoff because I can easily plug the intake with a 1.5" plug or ABS cap and nipple. (which I did today) just had to move a rock or two around, and plug the BH.. I also put threaded fitting on the ABS 90 towards the pump so I can modify that section if I ever want to change pumps and plumbing from the 90 to the pump.. So the section from the BH to the 90 externally will never need changing, just after the 90 on the outside..

While I was at I figured I would dump the union above the pump and that section of PVC and fittings.. I simplifed the connections there to eliminate any possible leaks.. I can post a shot of the new setup or do a drawing compared to the first one..

Well after it was all installed VIOLA!! MB almost NIL...or nil...MB...I dont know what part was sucking air in my setup but whatever I removed did the trick, I have my suspicions which section might be the culpret, but bottom line I conquered them! MB are now def doable at this point compared to what I was dealing with..Seems like most of what is in there if any at all are residue of the sump return... But also blowing around detrius too... but MUCH BETTER!!! wHOooHooo... I was NOT looking forward to re doing this only to see them white BASTARDS zooming out of my return again!

I may be upgrading pump and selling my p4 so I can power 4 returns..I really dont like the 1" tubing connectors on the pump, but on the positive side they act as a type of union that can be taken apart fairly easily for pump maintenance and or removal.

Here is the new setup from the 1.5" BH to the pump... Looks similar but it is really quite different..I dont reduce to 1" until right at the Barbed fitting. and there is no DIY ghetto ABS to 1" PVC as listed above...(that fitting that joined the ABS to 1" PVC was a DIY) All joints are real and either glued or stock threaded with Teflon tape.. I just wanted to eliminate ANY thing that might draw in air.

 

[Hef]

Sounds good. Really sucks to see those bubbles come flying across the tank doesnt it. I've heard so many things lately about my bubble problems. Thinkgs like "Ball Valves are known to suck air." I have to have a ball valve before the pump.

Anyway, over the holidays, I changed almost all of my outlet plumbing going back to the tank. I installed an Ocean Motion 4-way to the system. Took out a lot of Salt Creeped pipe and replaced it with very nicely glued pipe. Took out all of the Loc-Line fittings everywhere. Went with very basic 1" pipe back to the tank.
No Bubbles Anywhere - for about a week. Now they are back again.
Dolphin is a terrible company to deal with on the phone. They take an immediate defensive stand that there is nothing wrong with their pump. I'm trying to simply find out what size the "O" Rings are in the coupler fittings. Something around 2" but I want to find new ones. They said they would send me some, but they never showed up.

I Hate Bubbles

 

[drock59]

HEf, why did you remove the loc line. I hate bubbles too.