Tunze 9004 Regret

[Straasha]

I have a 55 gallon tank with the Fijicube AIO DIY kit. I am using the Tunze 9004 in the second of two chambers. The return pump sits below the 9004. The tank is fully cycled and has been up for two months. In order to keep the 9004 from constantly foaming over, I have to almost completely close the air valve. When I do this, it will soon start to constantly make popping noises. At most I can get it to work for one day before I have to tinker with the air valve or try to move the water level up/down. I have searched every forum for answers but nothing I read works. I have taken it completely apart and confirmed it is put together correctly. What can I do to make this not something I have to constantly play with to work? Is something wrong with the unit?

 

[rvitko]

First, make sure none of these items are in use, these will affect surface tension of the water and result in wet/uncontrollable skimming.

Seachem Purigen or other organic exchange resins, since these resins are intended to do the same job as a skimmer on tanks where a skimmer is not feasible, there is no reason to use it with a skimmer.
Non phenol free floss or socks (basically if you are using a media not intended for aquariums, it will usually contain phenol and this will cause the skimmer to go crazy until it is broken down, which usually takes a week or so)
Any organic additive, dechlorinator, stress coat, vitamin and amino supplements, carbon dosing, medications, algaecides. All of these will cause foam overs, their is no reason to use a water conditioner if you use RO water. There can be viable reasons to use the other products but when medicating or treating algae the skimmer should be off, for carbon dosing wet skimming is part of how the process works and for vitamins and aminos, a regimen of half the dose twice as often will reduce the negative effect on skimming.

If none of these apply, keep in mind adjustments are not instant, they take hours to show, be patient. Make an adjustment and wait. I am not familiar with this aquarium so assuming the water level stays constant in this chamber, I would start as follows. Unplug the skimmer, open the air all the way. Set the skimmer so only 1/3rd of the intake is submerged, keep in mind that if less than 1/4 is submerged the air control does virtually nothing, the skimmer has unlimited access to atmospheric air and is starved for water. Do not submerge it so more than 1/2 the intake is submerged and this depth must remain relatively consistent. Plug the skimmer in and work on the on the air adjustment. You generally do not want to exceed closing the air more than 1/3rd of the full travel of the screw, as you reduce air flow, water flow increases, the pump will pump the same amount, you are adjusting the air to water ratio. If you still have wet skimming with 1/3rd submerged and 1/3rd air closed, you could raise it a very small amount, about 1/8" or so. Beyond that I would dispose of the cup contents, it may be there is a surfactant substance in the water and you just need to remove it, after a week if no more of the substance is added, it will be removed or broken down, fresh activated carbon may help. Feeding foods that are high in cellulose/chitin and low in fat can also help a skimmer break in and absorb substances that may be causing problems for the skimmer, freeze dried krill is particularly good for this purpose.

 

[Straasha]

Thanks for the info. I do use RODI water and the only additive I occasionally add is RedSea NOPOX at half the recommend dosage. Even when I stopped using it for a week, I still have problems. When I submerge the skimmer from1/2 to 1/4 ( amount doesn't matter) and turn it on with the air fully open, it immediately starts to overflow. I have to almost completely close the air to get it to stop. Could the return pump being below the 9004 be the problem?

Here is the Fijicube AIO Kit that I have:

Fiji Cube AIO Box All-in-One Kit 3rd Gen - 55 Gallon Standard

Build your All-in-One (AIO) aquarium with Fiji Cube AIO box to maximize the fun of the aquarium hobby. Just drop this AIO box into a standard aquarium readily available in the market and your all-in-one aquarium will be ready to roll. The idea of this AIO box is to maximize the filtration...

www.fijicube.com

 

[rvitko]

I see no plausible way the pump could be a culprit. I would try the settings I suggested and just empty the cup, you can turn it down further but this tends to result in bubbles being ejected from the skimmer as the interval water flow becomes very high. NOPOX is basically a form of carbon dosing like Vodka or Vinegar, it feeds bacteria which then die and are skimmed out, this can cause very wet skimming. I can't really see a reason to use NOPOX on a 2 month old tank. Was the filter sock recently changed? Filter floss is a big culprit, most aquarium specific items are rinsed in manufacturing to remove phenols which are part of the production process, they cause overfoaming and can be removed by a long hot water rinse before use. It will typically take at least a week for the skimmer to work normally if phenols are added through floss/bags, emptying what collects and fresh carbon would be the best way to speed the process up.

 

[Straasha]

The filter socks are not new, I have been using the same two for the entire time. I have had the 9004 running the entire time as well. Thank you for your suggestions. I saw them on previous posts where you have tried to help others but none of them have worked for me. If I put the 9004 for in with the air completely open from anywhere to 1/2 to 1/3 in the water, it will fill the cup within 30 seconds. The only way to get it to stop is to almost completely close the air off until just a sliver is open. It seems that your are suggesting to just let it overflow for a week and see what happens?

 

[rvitko]

From a technical stand point, unless it was disassembled at some point and reassembled wrong, there is very little that can cause this. An AC synchronous motor on US power is always 3600 rpm, this speed is set by the Hz and cannot change. If some debris was snared on the needlewheel, this could cause more production, but typically the pump would struggle to start. I am puzzled, but from an electrical/mechanical stand point, there is no plausible cause of this. I would try emptying the cup several times and running some fresh carbon.

 

[Straasha]

Understood. I have taken it apart and verified it was put together right per the instruction manual. The air lines are not clogged, the needlewheel is not damaged, nor is anything blocking the water going in the motor. I will give it a few more weeks then start looking for a replacement skimmer.

 

[rvitko]

Before you go to that, lets double check everything with the impeller/air intake system. Try giving it a little more time and a photo of it actually installed and running might also help. We sell a lot of these skimmers and they generally get 4+ stars.

 

[kk.toronto]

I had the same popping (burping?) sound you are describing. For me the cause was gunk blocking the four tiny air holes in the lid of the skimmer cup, which was creating an airlock/suction situation. Unless the lid was removed or left ajar, foam would stop rising in the column and built-up air would back into the unit. The holes can be hard to see when they’re blocked, but they block easily when the cup fills up often.