Tunze Osmolater issue

[fishgate]

I just hooked up my Tunze Osmolater ATO today for the first time. It seemed to be working correctly and then the sensor started allowing water to fill to the secondary (emergency) shutoff. If I lower it back (remove water) it will work again perfectly and then start filling again after 5-10 minutes or so.

I cleaned the sensor off just to make sure nothing was wrong with it. I also soaked it in vinegar for about a 1/2 hour to no avail. A quick Google search shows that this is a fairly common issue going back at least 3 years or so. Is there a fix for it? Do I need a new unit?

I have the head unit about 20" away from the magnet mount. I also am using one mount for both sensors.

 

[rvitko]

These issues almost universally fall into one of these two categories and are issues with installation, contrary to what you might have perceived from a Google search, osmolator issues are quite rare, their are 10's if not 100's of thousands in use and the sensor will usually fail in the off position, constant green light and no fill.

1) First make sure bubbles are not present, the sensor only detects air vs water and if their are a lot of bubbles which can cling to the sensor, it will interpret this as being dry (in air). A soapy water rinse will reduce the attraction of bubbles to a new sensor but will not solve the problem if a lot of microbubbles are present, the sensor then must be moved to a calmer area with few or no bubbles.

2) Make sure the cause is not a siphon, i.e. you definitely hear the pump running and it is not just siphoning water in after the pump shuts off. This will occur anytime the water level in the reservoir is higher than the end point of the hose and is the most common culprit when the hose is secured to the sump rather than the tank.

 

[fishgate]

Thanks. There are no micro-bubbles in the return section of the sump. It is a 40B sump and the sensors are on the far side of the sump wall from where the water flows over the baffle. The flow is fairly slow. The surface has a few ripples. I will take a video of that also and post it here. The pump is definitely going on and stopping when the high water float activates. I will clean the sensor again tonight with soap and water. The unit works correctly if the water level is low and fills to about 1/2 way up the sensor and stops. Then between 2 and 10 minutes later the pump starts again and doesn't stop until the high water level float activates.

One of the similar failures that I read about said a power supply not delivering the proper voltage can cause this type of behavior. I will check that tonight with my multimeter and report the results here.

Thanks again!

 

[rvitko]

If the overall volume is low, you may need to turn down the pump rate, volumes of less than 40 gallons usually require this. This is covered on pages 42 and 43 of the manual. The controller deliberately overfills for 10 seconds after a fill is registered to reduce the number of off and on cycles per day, turning down the pump will reduce how much is added in this time. Another potential issue is anything causing the sump level to surge so it drops, triggers a top off and then rises, this is uncommon in most cases but can be caused by a clogged vent tube on a durso or stockman or a dirty HOB overflow.

The power supply delivering low voltage causes a very different issue, the unit will cycle off for a split second when the pump kicks on and cycle back on and you will repeatedly get the 4 start up lights blinking off and on.

 

[fishgate]

OK I just cleaned it with warm soapy water (dawn). I put the sensor back on and simulated a low condition by removing 1/2 a gallon of water. The unit filled as it is supposed to and stopped when it should. I let it sit for around 15 minutes and it started to fill again. Accept this time I got a whole new thing with it. See the video for what it does the low water light just flashes and it overfilled again. While it was having issues I removed the head and moved it around a bit to see if anything was going on with it. It did not seem to help unless I took it out of the water but it would not activate the pump.

<iframe width="640" height="360" src="https://www.youtube.com/embed/Z52WrQxs3yo?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>

<iframe width="640" height="360" src="https://www.youtube.com/embed/ohBdSwMZ4x4?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>

<iframe width="640" height="360" src="https://www.youtube.com/embed/vJersmFokUc?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>

 

[rvitko]

I will need to check the videos tomorrow in another browser, they apparently need Flash to be viewed.

The too low light will normally blink if after 10 minutes a fill is not registered, another possible cause is a source of electromagnetic interference affecting the controller. I will watch the videos tomorrow and get back to you.

 

[fishgate]

These are all youtube videos. I don't think there is any EM around the unit. The return pump is the only thing in the vicinity and it is a good 2 feet away from the controller.

 

[rvitko]

From the videos I can only gain so much knowledge.

1) The install looks good as far as being a calm area. I cannot really discern if any ballasts, etc are near the controller or sensors. I am skeptical about the controller install, it looks like the controller or DC tip could easily land in the sump, it just takes a brief exposure to saltwater while plugged in to destroy the DC tip, it essentially reverses the electroplating on the positive inner tip and results in poor contact. The controller of course is instant toast if it gets wet.

2) The reservoir is a little too close in height to the terminal point of the hose for my comfort. The pump can handle 8ft and personally I would always route the top off hose to my overflow box, making sure their is an air gap from the surface of the water to the top of the hose. At a minimum I would reduce how much hose hangs into the sump by at least 6", the end of the hose must be below the maximum water level you would keep in the reservoir to prevent a siphon and given the distant change in location, that may be the case, it is not clear in the video. In this video as best as I can tell, the water level sensor was not reached yet so the pump should be running. The display should show yellow and green on for 10-20 (usually 20 the first cycle 10 every cycle after) seconds after the water reaches the point on the sensor where the cone meets the cylinder. It should then change to green only.

3) The controller seems to show that the water is on the level sensor (green) which it is. The float is raised (red too high), which it is. And a blinking 2 low, which means the controller ran for 10 minutes and has timed out. The only scenarios I see this read out as feasible is the controller ran for 10 minutes and a surge in water level occurred due to a plumbing issue, a siphon occurred after a ten minute run time, or the controller has a defect. I would run the diagnostic test to rule out a defect, to do this the float must be down and the optic sensor must be dry, when you first plug it in, all 4 lights should flash, then you should get a green light, green means it passed, yellow means it is questionable which is usually caused by skin oils or some film on the sensor, red means it failed. Again, this test is only valid if the optic sensor is dry, when wet you will always get a red light.

 

[fishgate]

What is the DC tip? The power supply plug?

The controller is pretty tight there with the velcro plus I wrapped the cord around the plumbing (loosely) in case it does fall it will just hang there. But I can move that to a safer location.

The plumbing never causes a surge. But even if it did, that shouldn't cause the unit to continue to pump until the high water alarm is activated right? At worst it might cause the high water to pop up briefly then go off as the water level equalizes. But it doesn't surge at all. When it does overfill, the pump is running. It runs until the high water activates and then stops. It is clearly ignoring the optical sensor.

The ballasts for the lights are way up over the aquarium about 6 feet up. Also I will raise the water fill hose.

And just to cover all bases. What you saw in the video with the flashing lights is the first time it has done this. All of the other times it just fills to the right level, then between 5-15 minutes later is runs until the high water sensor trips.

I will run the diagnostic tonight.

 

[rvitko]

Yes, the end of the power supply that plugs into the controller.

What I have seen happen before is that the osmolator triggers a top off because the overflow is obstructed by a mat of algae or a sea cucumber, starfish or herd of snails, this suddenly clears and a bunch of water drains, the sump is then too full. This can also happen if using a durso or stockman pipe and the vent tube is clogged, the sump then tends to fill in surges like a toilet flushing.

 

[fishgate]

No there is no surge here. This is a brand-new setup no fish yet only had water about 2 weeks. It is dual drains (125 RR) and they drain fairly slowly just a trickle for each overflow. I can't imagine anything that I am doing wrong to this unit or the setup. It just came out of the box 2 days ago it is a totally clean install. I think the sensor is defective.

 

[rvitko]

Try the diagnostic and let me know, we can get the controller swapped out if need be.

 

[fishgate]

OK I ran the diagnostics with the sensor dry and it checks out with green. The unit flashes all lights when booting and then goes to green. A second later the pump activates and it starts to fill. I did notice that the sensor has been put together with a bit of a gap. Is it possible that this is leaking a little?

What else can I try?

 

[rvitko]

The gap should not matter, the two halves are assembled and from the wire entrance it is filled with polyurethane and that is what seals the unit.

With the hose routing changed, I would try it one last time. What you describe is the normal start up, passed self test.

 

[fishgate]

OK I just went and did some extensive testing. Every 5 minutes or so the unit starts to fill. If I put my finger on the sensor and kind of wipe it it stops filling and works properly for another 5 minutes or so then starts the process over. There is no time when it will go without erroneously filling for more then around 5 minutes.

 

[rvitko]

email your receipt with current address to- Tunze at sbcglobal dot net

 

[fishgate]

email sent, thanks!

 

[fishgate]

Well it looks as though I may have egg on my face.

My sump does not have a bubble trap in the return section. So I fashioned a temporary one that gets the job done. I don't have a lot of micro-bubbles but I do have some as my skimmer puts out a lot and they haven't totally dissipated by the time they hit the return section. I then plugged in the Tunze and have been letting it monitor the water level for about 14 hours now and it is working as designed. So I do not think there is anything wrong with it. I think the design of the optical sensor is overly sensitive to thinking it is out of water. So sensitive that I don't know if I can ever trust it. For now I am going to leave it as is and see how long it will go without failing. If it acts up again I am not sure what I will do. I may set up my controller with another float sensor to cut power to it if it overfills or maybe just set the two tunze sensors within about a 1/2" of each other. Worst case I will sell it and get a JBJ with mechanical floats.

Thanks for all the help in troubleshooting let's close this case out.

 

[rvitko]

They are far more sensitive when new, this does dissipate. The reason is simple, plastic is made from oil, as a result it repels water and attracts air, add to this that in the molding process a releasing agent is used so it pops out of the mold easily, like spraying a baking tin with PAM. This further aggravates the issue. The purpose of the hot soapy water rinse is to diminish this, I actually got that tip from an employee at a local company that makes light show technology for concerts, one of their lights relies on water running over the lens to create the effect and they have to really rinse them down in hot soapy water for it to work. Usually after a week or two, some bacteria have colonized the lens and really further minimized this effect to where it is a non issue and bubbles will not stick unless their are just tons of them. Even so, this is why we add the redundancy of a float and 10 minute time out and I think over time if you try another unit, you will see that the floats have reliability issues of their own, as the primary sensor they usually fail after a couple years and this is the best way so far to have a top off system that is safe and precise.