Burping BK Mini 200 skimmer problem

[neeper]

My BK Mini 200 was running great and all of a sudden it started a burp-like motion. About every 30-40 seconds of operation the foam head/water level in the skimmer drops suddenly, then rise back up. I can see a large bubble rise and hear a thump noise when it occurs. I opened the pump and inspected the resonator, impeller, and pump bearings; everything looks like it's in order. Has anyone experienced this or have any idea what could be causing it?

I have the skimmer submerged in 8" of water. Water line is right at the max line on the body of the skimmer.

 

[slief]

What model pump do you have with your Mini200? Is it an RD3 or the RD1?

 

[neeper]

It has the older pump, model 200 VS07.

 

[slief]

It has the older pump, model 200 VS07.

I would suggest a thorough deep cleaning. If there is friction anywhere inside the pump, that could cause the issue you are describing. The other thing it could be is if your wedge pipe is closed more than 50% you could be creating a siphon in the drain side of the skimmer. What happens is the level will rise until there is enough head pressure inside the skimmer to generate a full siphon at which point the level will suddenly drop. The fix for that is raising the sump level slightly. Maybe 1/2" and then opening the wedge pipe more or simply open the wedge pipe and see if it settles down.

For cleaning, please refer to this thread and also pay attention to post 2 in this thread discussing cleaning of the bearing since it applies to your pump. I would definitely look at the wedge pipe siphoning first but it is always a good idea to do a deep cleaning on your pumps. I recommend doing that every 4 months or so.
http://www.reefcentral.com/forums/showthread.php?t=2573406

 

[neeper]

Ok I'll try the two things and report back to you. Other questions I had was, when I opened up the resonator I noticed it didn't have the black sponge/foam inside it. Is this something important that it should have? If so where can I get a replacement?

Second, when I put the Skimmer cup lid on there's a humming noise. If I lift the lid off the noise goes away. Is this normal?

 

[slief]

Ok I'll try the two things and report back to you. Other questions I had was, when I opened up the resonator I noticed it didn't have the black sponge/foam inside it. Is this something important that it should have? If so where can I get a replacement?

Second, when I put the Skimmer cup lid on there's a humming noise. If I lift the lid off the noise goes away. Is this normal?

The foam is not critial. This is the replacment foam.
https://royalexclusiv.com/Spare-Par....html?MODsid=b3f6a21c4cbf2f43c0f20faeac842cb1

As for the humming, you likely just need to slighly loosen the screws that hold the motor base plate to the skimmer body to reduce/eliminate resonance from the motor but the deep cleaning may also help that if there is friction inside the motor which may cause vibrations. When you do your deep cleaning, follow the instructions in the link I provide. The first post in that thread discussed the RD3 but the same cleaning process applies. Don't soak the motor and impeller for more than 10 minutes when using pure household vinegar. That is more than enough to soften any buildup so the parts can be scrubbed clean and look like new.

 

[neeper]

slief, I did the deep cleaning as instructed and the impeller seems to spin a lot easier and smoother on the bearings now. Now I am still getting the burping action, is there anyting else I can try besides raising the my sump water level. I'm not sure how do that, is there like some plastic trim that can be clipped onto glass, kinda like the plastic ones that are used on shower doors.

 

[slief]

slief, I did the deep cleaning as instructed and the impeller seems to spin a lot easier and smoother on the bearings now. Now I am still getting the burping action, is there anyting else I can try besides raising the my sump water level. I'm not sure how do that, is there like some plastic trim that can be clipped onto glass, kinda like the plastic ones that are used on shower doors.

Not much more to try since I think the burping you are seeing may be from a siphon being generated in the drain side of the skimmer from the wedge being closed too much. Adding more water to the system should raise your sump level and allow you to open the wedge pipe more.

If it's not that, I would make sure the magnet is firmly attached to the impeller shaft. If the magnet is loose and slipping, you would need a new impeller. Outside of that and the siphoning mentioned above, the only other thing it could be is the motor but when they fail, they usually fail dead. As such, I would double check the magnet and make sure it isn't spinning or moving on the shaft and if it isn't, add some more water to your system to raise the sump level so you can open the wedge pipe more.

 

[neeper]

Reporting back... I was able to raise the water level in my sump. Avoiding the difficult route of gluing a taller piece of glass over my sump baffle, instead I decided to play with the Red Sea float switch located in the return section. The float switch connects up to the ATO reservoir up behind the display tank. I simply shaved down a bit of the plastic stop near the elbow of the float switch to allow it to swing up higher, hence raising the water level by a 1/2 inch, skimmer is now sitting in 8.5 inches water height.

Doing this has not only corrected the burping issue but the i have a consistent foam head at all times (without having to keep adjusting it). Before the foam head would collapse for hours throughout the day which had me thinking the skimmer was oversized for my 135 gallon setup. My previous skimmer was a Vertex Omega 150 which I always had to be constantly adjusted or it would overflow.

I am now super happy and impressed with this BK Mini 200 skimmer! Thank you so much slief!!

 

[slief]

Reporting back... I was able to raise the water level in my sump. Avoiding the difficult route of gluing a taller piece of glass over my sump baffle, instead I decided to play with the Red Sea float switch located in the return section. The float switch connects up to the ATO reservoir up behind the display tank. I simply shaved down a bit of the plastic stop near the elbow of the float switch to allow it to swing up higher, hence raising the water level by a 1/2 inch, skimmer is now sitting in 8.5 inches water height.

Doing this has not only corrected the burping issue but the i have a consistent foam head at all times (without having to keep adjusting it). Before the foam head would collapse for hours throughout the day which had me thinking the skimmer was oversized for my 135 gallon setup. My previous skimmer was a Vertex Omega 150 which I always had to be constantly adjusted or it would overflow.

I am now super happy and impressed with this BK Mini 200 skimmer! Thank you so much slief!!

Great to hear!!!!! I am very glad to help and especially happy to hear you have it working correctly now! That said, that skimmer is definitely oversized for your setup so you will have to keep it running wet to maintain consistent skimmate production. That or stock the heck out of your tank with LOTS of fish! FWIW, normally I’d suggest the Double Cone 180 for that size display but like I said, if you run it wet, that will help maintain consistency. The sump level adjustment you made will help with keeping it running wetter while also not having to close the wedge so much that you inhibit the flow out of the skimmer causing siphoning and surging within the skimmer.

 

[neeper]

Currently I have the water line inside skimmer about 1cm above the maximum line and about 1/2cm below the white acrylic collection cup base. I noticed there is still a slight burp with turbulence but not as large or often as before. Do you recommend I raise the skimmer to 9 inches or is 8.5 inches okay?

I wanted to ask you about that downsizing and it's interesting you mentioned the double cone 180. How does the double cone 180 compare to the mini 180? whats the benefit/advantage compared to each other? I was thinking stepping down to a mini 160 thinking the mini 180 would still be too large. Your thoughts?

 

[slief]

Currently I have the water line inside skimmer about 1cm above the maximum line and about 1/2cm below the white acrylic collection cup base. I noticed there is still a slight burp with turbulence but not as large or often as before. Do you recommend I raise the skimmer to 9 inches or is 8.5 inches okay?

I wanted to ask you about that downsizing and it's interesting you mentioned the double cone 180. How does the double cone 180 compare to the mini 180? whats the benefit/advantage compared to each other? I was thinking stepping down to a mini 160 thinking the mini 180 would still be too large. Your thoughts?

I’d probably raise it to 9” if your wedge pipe is 1/2 or more closed. I think the burping is more of a surge caused by a siphon being generated out of the drain side from the wedge pipe being closed too much. Raising the level will allow you to open the wedge more and should also make it easier to dial in from wet to dry since it won’t be as sensitive to wedge pipe adjustments. I do however think the level inside the skimmer is about right with it being just below the white part under the cup. It just boils down to how much you are closing the wedge pipe to get it to that level inside the skimmer. Next time you have it apart, be sure to check the magnet to make sure it’s not spinning on the shaft. While that is something that usually doesn’t happen, it can cause the skimmer to behave erratically. Given the improvements from the sump level adjustment, I don’t think that is the issue but it’s just something to be cognizant of.

The double cone has the RD3 and on the 180, 20-24 watts is about ideal for best performance. Most importantly, the Double Cone has the pump outside the body which makes routine pump maintence much easier since you don’t have to take the skimmer out of the sump let alone take it apart to do routine maintenance. If space is an issue than the Mini 180 is no slouch and it’s an absolutely terrific skimmer. Totally set it and forget it aside from adjusting the level inside the skimmer for wet or dry skimming. Either will perform much better on your size display given your lighter load.

 

[neeper]

Ok I raised the water level to 9" and still experiencing the burping problem. No matter how much I open the wedge pipe the burping/huge bubble still happens. I decided to pull the red wedge pipe out of the white tee fitting so there's no restriction and the burping still happens. The large burp/bubble is occuring on the side where tee fitting is.

 

[slief]

Ok I raised the water level to 9" and still experiencing the burping problem. No matter how much I open the wedge pipe the burping/huge bubble still happens. I decided to pull the red wedge pipe out of the white tee fitting so there's no restriction and the burping still happens. The large burp/bubble is occuring on the side where tee fitting is.

I’d pull the pump out and run it in some vinegar for 10 minutes then rinse it well and put it back onto the skimmer. If the burping continues, pull the pump apart and make sure the magnet is not spinning or slipping on the shaft at all and make good and sure the bearing is properly seated in the bearing cavity at the bottom of the magnet cavity. That is critical because any binding between the impeller shaft and that lower bearing will cause the impeller to stutter resulting in those symptoms. Beyond that, it could be a case where you just need to do more tuning of the nozzle. Opening the nozzle up more could solve it or you may need to close it more. Tough to say but if it’s not a case where the impeller is binding due to something you missed either in cleaning or properly inserting the bearing and it’s not a case of the magnet slipping on the impeller shaft than you need to do more tuning of the nozzle to tune the burping out as it would likely be getting too much water and not enough air or possibly vice versa which is where the adjustable nozzle comes into play.

 

[neeper]

Not sure what you meaning tuning of the nozzle... do you mean the wedge pipe?

 

[slief]

Not sure what you meaning tuning of the nozzle... do you mean the wedge pipe?

My bad. Not much sleep last night. I forgot you have the Mini and that pump doesn’t have the adjustable nozzle like the AC powered Double Cones and older Supermarin and Deluxe skimmers. So disregard the nozzle part and focus on running the pump in some straight vinegar for 10 minutes or you can dilute the vinegar down to 50/50 water and vinegar and run it for a few hours. That will insure that any calcium that may not have been removed from the bearing in the rotor plate and the bearing in the lower part of the motorblock is cleaned out. Then retest. If the issue persists, take the pump apart (again), double check the magnet to make sure it’s not moving on the shaft at all and triple check the bearing inside the magnet cavity to make sure it’s seated properly and in the correct orientation. See the post 2 of this thread below for the bearing installation and orientation. It’s the same thread I pointed out eariler.
http://www.reefcentral.com/forums/showthread.php?t=2573406

Outside of the above, the only other things it could be is the motor block failing which I doubt since when they fail, they usually fail dead. Or the needle wheel hitting the inside of the pump cover. If it was that, you should be able to see wear marks on the face of the needles and or rub marks on the inside of the pump cover from the needle wheel hitting the inside and rubbing the inside of the pump cover. Also doubtful unless the impeller was tuck at one point and you pulled on the needle wheel too hard to get the impeller out and accidently pulled the needle wheel up on the shaft away from the magnet. And last but not least, if the bearing isn’t seated properly in the lower part of the magnet cavity as that could cause the rotor to sit too high in the magnet cavity. Now if the bearing isn’t seated properly, that could also cause the impeller to bind and that would cause an intermittent stall of the motor which would exhibit the issue you noted since the motor would stall for a brief moment intermittently stopping the flow.