9004 DC not surface skimming in countercurrent mode

[Fritz05]

I installed the motor housing cover on my 9004DC and raised it so that the intake is only a third or so submerged, but it is not surface skimming. I took it apart and cleaned it, but that did not help either. I cannot see that water is flowing into the intake, surface particles just pass by it. Any suggestion?

 

[Clownfishy]

I had the same problem but putting the pump cover on solved this. Does it surface skim if you move the skimmer up so the intake is just below the waterline by a millimetre or two?

 

[rvitko Verified Sponsor]

As clownfishy said, raising the skimmer is needed if you are trying to remove surface film, if it is submerged deeper, it is surface skimming but this film has a surface tension and sticks to itself and is not sucked in, it is taking the water right below that, raising it until it skims this film will solve it.

 

[NCsalt]

Is your tank rim or rimless? If rimmed make sure the extensions are on magnets. I find it needs to be level to skim properly. Also adjust height of skimmer until you see water trickling behind weir you will also hear it as it gets louder. Its a fine line of water level of tank to proper surface skimming and so ato is very important ime. Did you clean the tubing line? If it starts under performing there could be salt creep in line simply unhook line from silencer and put maybe 10 mm of white vinegar in it with skimmer off. After 10 minutes put end of tube in tank and turn back on. The tank water will be sucked down the tube and clear it. Then hook it back to silencer.

This is a great skimmer there are just a few tricks to keep it performing optimally.

 

[Fritz05]

Thanks for all the advice. I need to add that the skimmer used to surface-skim, I have the motor cover installed for months, and it worked fine.
My tank is rimless and the skimmer level. I cleaned the entire device, including the foamer and airline, removing the salt creep, and raised it to different levels, it currently sits only 2-3 mm below the waterline. I turned off all wavemakers, but even with a non-moving surface there is zero observable flow into the skimmer, even though it is producing nice foam and skimmate. To test further, I installed my 9012DC with the motor housing installed, and it cleaned the surface within 5 minutes.

I do not know what else to try.

 

[rvitko Verified Sponsor]

Are all the interior panels correctly lined up? Is the cap on the rear bottom possibly removed (translucent plastic cap)? I know this video is not great, it is my first attempt at one, but generally if you have no skimming, something is in wrong.

 

[Yodaman]

Are all the interior panels correctly lined up? Is the cap on the rear bottom possibly removed (translucent plastic cap)? I know this video is not great, it is my first attempt at one, but generally if you have no skimming, something is in wrong.

This video was very informative, and extremely helpful, as I bought my 9004 second hand, and it came with no paperwork! I’ll be taking mine apart this afternoon!

 

[NCsalt]

The fact that it was skimming surface skim and now its not is intriguing based on what you have done in relation to cleaning. I would think that there is something not put back together correctly disturbing flow of the unit. Thats my best guess, but who knows. Keep us updated so we can address it with ours if the same problem arises for other product users.

 

[rvitko Verified Sponsor]

Yodaman, thank you, I plan to redo it eventually, I have a tank at the office now and can show troubleshooting bubble issues and I can get better shots and audio.

 

[Fritz05]

I took it apart and reassembled it again. But as shown in the video, there is no surface skimming. When I turned off all pumps there was the slightest movement of water into the skimmer, but with the pumps on there is nothing.

 

[Clownfishy]

Is the skimmer generating much foam and how far up the skimmer collection cup is the foam going? Just wondering if the pump is not working as it should and has lost some of its power?

 

[rvitko Verified Sponsor]

As clownfishy said, and it is important to point out this pump is only drawing around 150-250 gph of water, in no case will this suction be very strong and surface film can be quite stubborn, it has an attraction to itself and is repelled by the water and when it is abundant this can prevent much removal, flow can also create islands that cannot reach the surface skimmer as the pattern walls off the waste from reaching the skimmer. What speed is the pump set to? Generally a 9004DC should be running at about 30-40% pump speed and producing wetter skimmate. If the impeller was accidentally swapped with an AC impeller on US models it will be underpowered. AC impeller is 9004.047 and DC is 9004.049, on 50Hz models the impeller is the same. I would check that if you hold the magnet portion of the impeller and turn the needles the fit should be slightly stiff and reach a hard stop at 270 degrees either direction, free play here could be a cause, the needlewheels are slipping and not spinning at the rate of the magnet, if the pump ever siezed, this can depolarize and weaken the magnet as well.

 

[Fritz05]

Pump is set to 40%, and I never changed the impeller. If I turn off my pumps it does surface skim a bit, so will do that periodically. The foam goes up the skimmer about half way. Thanks again for all the help.

 

[rvitko Verified Sponsor]

I would try turning up the pump a bit, the foam half way up the riser is just a basic guide that is useful for beginners but not the most accurate way to set a skimmer, it should be adjusted by what collects in the cup and for a small skimmer, something like iced tea would be appropriate, it won't generally skim dark and thick as their just is not the surface area and volume to dry the foam to that level in a small skimmer.