Tunze 9016 not producing foam

[ianjirka]

Hello,

I have a Tunze 9016 that hasn't produced foam for about three weeks now.

A little history first, in case it's relevant:
I bought the skimmer in Jan/2011, put it into service on 7/1 (Everything takes longer than you think!). This was the same time I put LR into the tank, and it started producing foam immediately. It was quite simple to set up. I cleaned the skimmer body after about 4 months (good scrubbing, no vinegar or other acid), and cleaned the riser about once a week. None of that ever affected my output. I keep the skimmer with the 'cabinet' kit attached, at the recommended waterline level. My sump water level is very stable in this chamber. I don't see a lot of turbulence in this part of the sump.


About three weeks ago, I decided to take out the SSB from my DT. Too much sand was blowing around and I replaced it with a epoxy/sand/pvc sheet false bottom. I used the 'pour-on' brand of epoxy and let it cure ~3 weeks before putting it in the tank. The SSB removal was as gradual as I could make it, taking sand out over a 2 month period until I had to take the rocks out to get the rest.

The skimmer remained on in the sump, operating via a temporary closed-loop system I set up while the main pump was off.

Since then, the skimmer has produced 0 foam. I'm pretty sure my tank hasn't suddenly become sparkling clean

I've tried all the tricks I could find:
- Ensured the silicone tube is not kinked. It has a tendancy to kink (that is how it arrived), but not the way it is laid out in the skimmer now
- Giving it a good cleaning. Haven't used acid but so far haven't encountered any calcium or other deposits
- Disassembling the silencer and cleaning it out, ensuring the entire airway is clear.
- Opening the air screw full, half, almost closed, leaving it alone for a week, etc.
- Double checking to see if anyone else using pour-on had any negative affects in their tank or otherwise. None that I could find and it seems a pretty popular choice for this application.
- Swapping out parts with an extra 'cabinet filter' kit I had purchased
- Going through the manual/troubleshooting guides

Nothing helps.

Some clues:
-I get more fine air bubbles in the output than I used to
-I don't get enough pressure in the output unless the skimmer is mostly submerged (~2 inches of pipe out of the waterline). Water is being drawn in between the gap of the bottom plate and the skimmer body. If I hold that gap closed, the skimmer can produce enough pressure to operate with 3-4" exposed. Replacing the bottom plate did not help.
-The skimmer produces fine air bubbles out through the bottom plate. They collect on the bottom of the skimmer.
-The pump runs fine (as far as I can tell at least) in freshwater when removed from the skimmer body. No obvious problems with the impeller, motor or venturi.

Hopefully this is enough info to help and I'm happy to try any suggestions. I'm sumped!

Thanks much,

-Ian

 

[rvitko]

Water should be able to exit the standpipe as long as at least 4" of the skimmer are submerged, the bottom plate is only part of it, and it will not be tight, but should be closed all the way. I would double check the part 9010.400 sleeve below cover, be sure it is in so it is securely over the pump intake and that the front screen is fully open.

Epoxy does tend to interfere with skimming, but not once cured, if some dust or residue was flaking off and being stirred up, this may be a culprit but unlikely.

On some early units the airline was too long, when outstretched the airline should hang down about 1/2-1" below the bottom of the body, if it is longer than that, you can cut it to the correct length. This should solve the kinking problem.

Make sure the pump output nozzle is installed into the clear pipe in the skimmer body.

 

[ianjirka]

Thanks Roger

Water should be able to exit the standpipe as long as at least 4" of the skimmer are submerged, the bottom plate is only part of it, and it will not be tight, but should be closed all the way. I would double check the part 9010.400 sleeve below cover, be sure it is in so it is securely over the pump intake and that the front screen is fully open.

I have checked these before, will double-check tonight.

On some early units the airline was too long, when outstretched the airline should hang down about 1/2-1" below the bottom of the body, if it is longer than that, you can cut it to the correct length. This should solve the kinking problem.

Good to know, thanks. Is there a way to order a replacement? (or can you confirm the ID and OD of the tubing?) It has remembered the kink point, and while I haven't seen it be a problem, it would be nice to eliminate the propensity to kink at that spot.

Make sure the pump output nozzle is installed into the clear pipe in the skimmer body.

Will do, thanks.

 

[rvitko]

The airline is not easy to replace, I can certainly send a length, but I might try just soaking it in hot water while assembled and stretching it, usually silicon tubing doesn't have the "memory" of PVC tubing and kinks can be worked out by some heat and stretching. It is hard to work in the confined space, every time I do silencer repairs I inevitably end up with bloody knuckles.

If you just PM me your address I will send the tubing.

 

[ianjirka]

The airline is not easy to replace, I can certainly send a length, but I might try just soaking it in hot water while assembled and stretching it, usually silicon tubing doesn't have the "memory" of PVC tubing and kinks can be worked out by some heat and stretching. It is hard to work in the confined space, every time I do silencer repairs I inevitably end up with bloody knuckles.

If you just PM me your address I will send the tubing.

Thanks Roger, I will send you a PM shortly. I checked the various things -- all look fine and the parts fit together well. I gave it another cleaning -- I missed the tube the hydrofomer outputs into -- and double-checked the airway holds pressure well. All good. I also tried the heat/streching method. It might have helped a bit, but I still have the kink. I just used hot water, maybe that's not hot enough.

I'll let it run for a day or so and see what happens.

Cheers,

-Ian

 

[ianjirka]

So, two days later and it's not producing skimmate. It is producing foam/scum outside the skimmer in the sump chamber :-(

Right now the bubbles (white "foam") are coming up level to the top of the housing (black opaque part). I'm using the 9020.140 "foam extraction unit". The air screw is about 5.5 turns out.

Any thoughts?

Thanks,

-Ian

 

[rvitko]

We did mail the new airline today. I would try a thorough cleaning and to do this, I simply buy a gallon of white vinegar, take an old salt bucket (tall 7 gallon size bucket or something comparable. Insert the skimmer in the bucket, complete except the cup or foam extractor, blue screw removed completely. Add the gallon of vinegar and enough warm tap water to cover the skimmer completely. Plug in the pump and let it run overnight, this will dissolve any salt creep in the air intake and any calcium build up in the venturi.

Has anything changed with regards to additives or tank maintenance or food used?

 

[ianjirka]

We did mail the new airline today. I would try a thorough cleaning and to do this, I simply buy a gallon of white vinegar, take an old salt bucket (tall 7 gallon size bucket or something comparable. Insert the skimmer in the bucket, complete except the cup or foam extractor, blue screw removed completely. Add the gallon of vinegar and enough warm tap water to cover the skimmer completely. Plug in the pump and let it run overnight, this will dissolve any salt creep in the air intake and any calcium build up in the venturi.

I will try this.

Has anything changed with regards to additives or tank maintenance or food used?

The only thing I've done differently around the time the skimmer stopped producing was
1) Added 1/8c GFO in a ~200g water volume system(runs about 10hr/night) as a trial. I did this 6 days prior to removing my DT SSB and didn't notice any change in the skimmer
2) At the same time as #1 moved from Liginite to ROX.8 carbon (3/4c)
3) Removal of the SSB

Other than that, nothing really different. Still using the same food(s), CA/Alk/Mg suppliments when needed. Have increased my Kalk usage over time... Ph runs slightly higher (peaks around 8.5 vs 8.35 a few months ago), but nothing out of the norm I think. Can't see anything else. Is there something you have in mind? I know some additives/foods can change skimmer behavior. I see it when I get my hands in the tank, the skimmer will stop for a few hours, but always resumed. Otherwise it's been pretty consistent in the past.

If there was something in the tank affecting the skimmer, I'd expect the carbon would have worked it out by now. Also I think it would have the same affect on the gunk that the small bubbles in the sump chamber have created. Or is this not typically the case?

Thanks much as always,

-Ian

 

[ianjirka]

Okay, I tried as you suggested and gave the skimmer a vinegar bath. It came out looking like new. I ran it at the recommended '6 turns out' airscrew position. It produced a pretty wet skimmate for a few hours (about 1/8 cup), then returned to foaming just below the top of the skimmer body. It's been that way for the past ~48 hours.

I looked around on youtube for what the skimmer should look like while operating -- I didn't find many videos, but those I did showed a lot more production than I've ever seen out of mine.

So, not sure what to do at this point. I'll try with the new airline when it arrives (thanks!), if you have any other thoughts I'd appreceate it. Thanks for answering my [many] questions so far.

Cheers,

-Ian

 

[rvitko]

You mentioned small bubbles in the sump collecting gunk, while this would be an extreme case, I did have a customer whose plumbing basically acted like a skimmer, the waste was being collected as a brown foam at the drain pipe before the skimmer, this also modified many of the organics and the skimmer performed very poorly. The solution was changing the plumbing and slowing the flow through rate. Other than that, I could only recommend sending it in or trying it on a friends tank.

 

[ianjirka]

I think it is related to the pump. It won't pump water through the outlet pipe if the outlet pipe is more than ~1.5" out of the water. It should be able to pump with most of it out of the water.

Is there anything I can try to see if it is a problem with the pump itself or if the pump input/output is restricted somehow?

What's the process for sending it in, if I need to do that?

Thanks,

-Ian

 

[rvitko]

It could be the pump, it could also be something is off with how the sump kit is installed.

To check the pump, remove it and run it in a sink or bucket, the jet should be fairly forceful, if held just at the surface it should produce a roughly 2ft geyser, if it is just a 4"-6" bubbling fountain, the pump is likely spinning backwards.

Otherwise, be sure part 9010.400 is installed so it is over the intake of the pump, also the bottom plate must be the solid one with the suction cup feet, it must be in completely and correctly so the bevelled edge faces forward and it should be resting on this base. The front intake grate must also be open completely.

You would just send it in without the cup-

Tunze USA
305 Victor St
Austin, TX 78753

 

[ianjirka]

It could be the pump, it could also be something is off with how the sump kit is installed.

To check the pump, remove it and run it in a sink or bucket, the jet should be fairly forceful, if held just at the surface it should produce a roughly 2ft geyser, if it is just a 4"-6" bubbling fountain, the pump is likely spinning backwards.

Yup, a 4" fountain. So this seems to be it. I bought it in Jan '11, so about the right timeframe (From what I read in other posts). Man, I'm going to feel like even more of a n00b if it's been running this way the whole time :-/

Is this something I can fix and/or what should I do next?

Thanks Roger,

-Ian

 

[rvitko]

This problem is caused by a sensor in the motor and it is not repairable, the motor has to be replaced. Send me just the pump and we will replace it. Likely it would have been doing this since the beginning though it may start in the correct direction occasionally and this could explain why it worked better in the past.

 

[ianjirka]

This problem is caused by a sensor in the motor and it is not repairable, the motor has to be replaced. Send me just the pump and we will replace it. Likely it would have been doing this since the beginning though it may start in the correct direction occasionally and this could explain why it worked better in the past.

Will do. Thanks for helping me figure this out!

-Ian

 

[ianjirka]

Got the new pump on Tuesday -- it's been producing gobs of foam ever since. Thanks for spending all the time to help me figure out what the problem was!