# API XP3 Canister Filter has lots of air bubbles coming in the intake



## sushant (Mar 3, 2007)

have you checked the tubings chances are they are not tightly secured because a defective/displaced o-ring would have resulted in a leak.


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## GreenTank1 (Nov 25, 2012)

Yes. I did check those again and the hoses are all securely attacked using metal clamps as the plastic ones that came with it were junk.


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## Midnighttide102 (Oct 2, 2014)

I have 2 of the same filters there great been running over 5 years not a prob 
Try cleaning the inside of your intake pipe sometimes they can get pretty gunked up also check the cap on the intake pipe 
The Impeller also sounds like you might have to pull it out clean it lube with vasaline if your flow has slowed down 
They way you stack your media also makes a big difference


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## GreenTank1 (Nov 25, 2012)

I haven't ever put lubricant on the impeller after cleaning. That could explain why a couple of my HOB filters broke in the past...I'll try what you recommended tonight. For a little more information I neglected in my original post, I have a high flow prefilter on the intake which has a java fern attached so I haven't cleaned that for a year or more. I assumed the SAE and fern were taking care of keeping it clean, but I am sure that is causing much of the flow restriction. 

Obviously the flow rate needs to be addressed, but I am more concerned with the bubbles coming in as it is causing the water line to drop to the point where the motor doesn't get any water to cool it/lubricate it and causes it to stop working entirely. The restricted intake could cause those bubbles? Or is there something else I need to consider to address that problem?

Also an update to my earlier post, I have had this tank for 2 years. I didn't realize how quickly time had passed.


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## dmagerl (Feb 2, 2010)

Does it spew bubbles from the output? Does it only do it at the end of the day?

Air in the filter doesnt necessarily have to come from air leaks. It can come from the water itself, much like opening a bottle of soda.

I have an XP3 and I'm beginning to hate it. Mine does the same thing, the water level in the filter gradually drops and it spews bubbles out the output. But I noticed that it only spews bubbles in the late afternoon, never in the morning. I eventually correlated this with the level of CO2 I was injecting.

I shut the CO2 off at night so in the morning CO2 levels are low and become highest right before lights out in the afternoon. Corresponding with the spewing of bubbles only in the afternoon.

To test this hypothesis, I ran without CO2 for a few days and experienced no spewing, no level dropping, it just worked great. Turning CO2 back on again led to spewing of bubbles. And no, it was not due to the ingestion of CO2 micro bubbles up the intake pipe and it was not due to an overdose of CO2, the drop checker was barely green.

So right now, the XP3 sets a limit on how much CO2 I can inject. If I turn the needlevalve down a notch, everything runs just fine. But if I go any higher with the needlevalve, I get XP3 problems.

So do a test. Burp the filter by unhooking just one of the lid hold down clasps with the filter off. Bring the water level in the filter to the bottom of the lid and re-attach the clasp. Then just run it for a day or two without CO2 and see if the problem goes away. IF so, you've found the problem.

If not, I'd say you have something obstructing the input side of the filter, either a build up of gunk in the intake strainer, too much floss in the filter basket, or anything else that would make the effective diameter of the intake hose less than that of the outtake hose. Air/CO2 will come out of solution if there is a pressure difference. An input restriction will accentuate this.

Another test to try is to reduce the size of the outtake hose to build some back pressure. My XP3 came with a shutoff valve on the spray bar. Try cracking that closed a bit to reduce the flow through the filter and see if that helps things. This serves to reduce the pressure gradient across the filter.

In my experience, the large seal around the lid is seldom the cause of leaks. More likely are the O-rings in the quick disconnect. If you're sure its sucking air from somewhere, I would dismantle that part (there're two big screws holding it together but dont do it with water in the hoses) and lube the o-rings with some silicone grease. Then lube the o-rings that seal it when plugged into the canister.


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## Bushkill (Feb 15, 2012)

I run 2 of them on my 180G. Try pulling and a re-seating the quick-connect assembly back onto the pump housing. while you have them apart, take a look and make sure there isn't anything there that can keep the seals from seating properly. It's pretty sensitive to not being firmly seated. Aside from the primer cap or bubbles being produced in the tank, that's about the only way for air to get introduced into the canister body.


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## GreenTank1 (Nov 25, 2012)

dmagerl, I have a large cerges reactor that diffuses any possible micro bubbles that would exit the filter so I wouldn't be able to see that very well. I did re-arrange my filter floss configuration a little bit to give more room for my bio filtration portion in the canister so I may have to put it back. 

I did do the burping thing on my filter last night after the CO2 was already shut off and within 5 minutes the water line was already down a couple inches from the top. However, I have noticed over the past month or so (after my most recent CO2 refill) that no matter how much CO2 I push through the system, the indicator never gets into the strong green or yellow color I used to see when I pump the same amount through the system. I wrote that off as my indicator fluid being old, but based on what you are saying, there could be a leak in that portion of the system even when it is turned off. I definitely see a steady steam of bubbles going through the intake tube the from the top though so I am pretty sure the bubble are being introduced at that section. When I turned off the filter after it dropped a couple inches, it immediately went back up about an inch. That would also support your theory on the intake being more restrictive that the outflow. My version doesn't have a spray bar, but I do have a valve on the outflow that I can partially close to test that theory.

Bushkill/dmagerl, The O-rings that are visible on the quick connect assembly look to be in great condition. I had tried to re-seat that part multiple times with no success, but I will take it apart if the other suggestions do not work.

Thank you all for the advise. I'll let you know tonight if I have success.


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## FatherLandDescendant (Jul 24, 2014)

GreenTank1 said:


> I did just do a canister cleaning recently and noticed that the large o-ring was a little loose, but otherwise looked to be in great shape.


Did you replace this o-ring? Loose indicates being stretched, this can occur and not damage it in other ways, IE nicks, cuts, gouging, or tearing.

O-rings should fit snug into their channels, if they are loose they can leak. Restricted intake flow can cause suction buildup inside a filter and stretch the o-ring and cause it to leak. Remove the Javafern you mentioned in another post on this thread, that sounds like a restriction issue to me. While JF doesn't feed through its root system it still generates rhizome growth, which I'm guessing is the source of your restricted flow issues.

IMHO if you remove the JF, and replace the stretched o-ring it should solve your problem.


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## GreenTank1 (Nov 25, 2012)

At lunch I did a quick trial and switched the prefilter out for the original intake strainer and it it looks like all the issues were fixed. Tonight, or when I can get around to it, I will definitely remove that JF (which had grown roots through the filter and into the substrate below). That makes sense about the extra suction because when I tried to burp the filter with it running, there was no way I was getting any air in without forcing the lid up. I'll order a replacement online tonight as well. Thank you all again. I was about ready to go to the lfs and get an overpriced replacement as things tend to be where I live.


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## Midnighttide102 (Oct 2, 2014)

Glad to hear u got the issues resolved , don't forget to keep your impeller lubed


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## dmagerl (Feb 2, 2010)

My XP3 is very sensitive to intake strainer blockages. Whenever it starts spewing bubbles, I immediately check to see if the strainer is blocked and usually it is.


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## jimbo662 (Aug 4, 2013)

A friend of mine bought the XP3 a couple of weeks ago and had issues with lots of air seeping into the intake line. Turns out the U shaped attachment with the screw on cap was defective and allowed air to seep in. They replaced it and all is fine now.


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## Clear Water (Sep 20, 2014)

Mine has always been the main gasket. Like others have report if air leaks out of the return it should be sealed. I have a foam prefilter and it never been issues. One thing I have done that's helped this problem is to take a rag and screwdriver and clean the track the gasket fits in.


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## Bushkill (Feb 15, 2012)

jimbo662 said:


> A friend of mine bought the XP3 a couple of weeks ago and had issues with lots of air seeping into the intake line. Turns out the U shaped attachment with the screw on cap was defective and allowed air to seep in. They replaced it and all is fine now.


I have to hand it to them for customer service. Every product delivers a clunker every now and then, but the quality companies make good, and API does it fast and painlessly.


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## crazy4fids (Dec 3, 2014)

Midnighttide102 said:


> Try cleaning the inside of your dia also makes a big difference


How does this make a difference? I just purchased a used fluval 405 with no media and no instructions. I think I may have the media stacked backwards.[emoji5]


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