Tunze Osmolator Problem Back Flow/De-priming

[Joshua M Hall]

Anyone ever have a problem with what seems like the Osmolator will flow back into the ATO FW Reservoir after it turns the pump off? This is the only thing I can think of that is happening. I have a head pressure (think that's what its is called?) of about 2 feet from pump to outlet. It doesnt happen all the time but a couple of times in the month I have owned it, it has happened and the pump either doesn't get water going at all or it takes 30 seconds to a minute. The first time it happened I thought it was cause I had the pump set too slow and I adjusted it all the way up and it still didnt pump water up and out. Im not sure if it became air locked or something. I have thought about buying a check valve to see if that would help but one I'm not totally sure this is the problem and two not sure which check valve to use. Anyone ever dealt with this issue?

 

[FirstContact]

I used RO tubing on mine with a check valve. I specifically used the check valve because I had it pushing through a Kalkreactor.

 

[Joshua M Hall]

I used RO tubing on mine with a check valve. I specifically used the check valve because I had it pushing through a Kalkreactor.

Where did you get the check valve and which one was it? (size)

 

[pugcrush]

Anyone ever have a problem with what seems like the Osmolator will flow back into the ATO FW Reservoir after it turns the pump off? This is the only thing I can think of that is happening. I have a head pressure (think that's what its is called?) of about 2 feet from pump to outlet. It doesnt happen all the time but a couple of times in the month I have owned it, it has happened and the pump either doesn't get water going at all or it takes 30 seconds to a minute. The first time it happened I thought it was cause I had the pump set too slow and I adjusted it all the way up and it still didnt pump water up and out. Im not sure if it became air locked or something. I have thought about buying a check valve to see if that would help but one I'm not totally sure this is the problem and two not sure which check valve to use. Anyone ever dealt with this issue?

Is your pump upright? If the water gets too low, you have to siphon it again. I like to lay my pump on it's side. Never an issue with this route.

If it's flowing back to your ATO container, that's certainly a whole other issue. Sounds like your issue is the first statement, but just in case; make sure your ATO output somehow isn't getting submerged and your ATO isn't above the ATO output.

 

[Joshua M Hall]

Is your pump upright? If the water gets too low, you have to siphon it again. I like to lay my pump on it's side. Never an issue with this route.

If it's flowing back to your ATO container, that's certainly a whole other issue. Sounds like your issue is the first statement, but just in case; make sure your ATO output somehow isn't getting submerged and your ATO isn't above the ATO output.

Im a bit confused. If I laid the pump on it's side then it seems like it would be more susceptible to lower water levels since you would be accentual raising the intake higher. I figured you would want it straight up and down so that the intake would be at it's lowest possible point in the reservoir.

 

[pugcrush]

Im a bit confused. If I laid the pump on it's side then it seems like it would be more susceptible to lower water levels since you would be accentual raising the intake higher. I figured you would want it straight up and down so that the intake would be at it's lowest possible point in the reservoir.

I've done it both ways. After some extended times away from the tank, I feel I can get an extra day or two with it on it's side before having to be refilled. Ever since then, I've kept it on it's side. This trick works for my parents setup. I usually have to give instructions for my dad.

Nevertheless, did allow the pump to siphon the first time starting it up? If not, it will have air trapped & probably end up losing the siphon. Also, if the pump gets exposed to air, your have to do it again.

Just another thought, but has your power gone out at all during these situations?

 

[FirstContact]

Where did you get the check valve and which one was it? (size)

Bulk Reef Supply 1/4” for RO tubing Murlock.

 

[Joshua M Hall]

Bulk Reef Supply 1/4” for RO tubing Murlock.

Ive looked for what you said and dont see it. Anyway you could post link? Thanks for the help!

 

[FirstContact]

https://www.bulkreefsupply.com/mur-lok-inline-check-valve-1-4-x-1-4-push-connect.html

Here it is!

 

[drtrash]

So where does your ato pump water to? Sump, tank, overflow? I would assume is water resivoir is on ground level and so is sump its possible to get backflow. Try raising the return line so head pressure may stop backflow. I have heard of drilling hole in line to break siphon like retutn on tank

 

[Mako61]

I use a piece of PVC tubing into my sump. I stick the line from the ATO in the top. The top of tube is higher than ATO. The tube is smaller than the PVC so no seal. Works great and very simple.

 

[Joshua M Hall]

So where does your ato pump water to? Sump, tank, overflow? I would assume is water resivoir is on ground level and so is sump its possible to get backflow. Try raising the return line so head pressure may stop backflow. I have heard of drilling hole in line to break siphon like retutn on tank

My fill tube goes into my sump on the back of my IM20. The pump and reservoir are located about 3 feet below the top of the tank and end of the fill tube. What I think is happening from time to time is that once the pump turns off the water runs back down the tube and back into the reservoir thus causing issues when it kicks back on. This is only a guess.

 

[Joshua M Hall]

https://www.bulkreefsupply.com/mur-lok-inline-check-valve-1-4-x-1-4-push-connect.html

Here it is!

Thanks!

 

[Wy8tt_Earp]

I had the same problem a while back. After speaking with Tunze I raised the return line to the back of my overflow and, most importantly, made sure the return line was not submerged under water. This will allow only the water in the line to naturally flow back into the ato reservoir.

 

[Joshua M Hall]

I had the same problem a while back. After speaking with Tunze I raised the return line to the back of my overflow and, most importantly, made sure the return line was not submerged under water. This will allow only the water in the line to naturally flow back into the ato reservoir.

Can you explain a bit? When you say you raised the return line to the back of the your overflow what do you mean?

 

[Wy8tt_Earp]

Originally I ran the return line to my sump which was lower than the top of source. By raising the return line to the overflow on the back of the tank I eliminated the back flow or the need for a check valve.

 

[Sleepydoc]

The Tunze pump is a simple centrifugal pump. I found mine to be very prone to air bubbles and have a hard time priming itself. If my ATO every went dry and the pump sucked in some air, it would take forever to re-prime itself. Shaking it under water while it was running usually did the trick.

In terms of back flow, the tubing can and will form a siphon. If the outlet is submerged in your sump and the water level of the ATO reservoir is below that of the sump, water will flow backwards until the siphon is broken, the water levels equilibrate, or the ATO kicks in again. In a similar vein, if the end of the tubing is lower than the water level in your ATO reservoir then water will continue to flow until the ATO water level either drops below the end of the tubing or the reservoir is empty.

Set up properly, there will likely be a small amount of back flow as the tubing empties, but shouldn't be more than a few ml and shouldn't affect the pump prime.

Think of it like having a bucket of water on the floor next to the display tank and a small pump with tubing going up of the edge of your display tank. You turn the pump on and it pumps water. Once you turn it off, all the water that is in the tubing drains back into the bucket. If the end of the tube is below the water surface in the tank, then a siphon starts and water keeps flowing until something happens to break the siphon.

Now if you have a similar setup but have the bucket on a shelf above the tank, once you turn off the pump, you have a siphon started and water will continue to flow from the bucket down to the display tank until something breaks the siphon.

 

[Mav2]

The Tunze pump is a simple centrifugal pump. I found mine to be very prone to air bubbles and have a hard time priming itself. If my ATO every went dry and the pump sucked in some air, it would take forever to re-prime itself. Shaking it under water while it was running usually did the trick.

In terms of back flow, the tubing can and will form a siphon. If the outlet is submerged in your sump and the water level of the ATO reservoir is below that of the sump, water will flow backwards until the siphon is broken, the water levels equilibrate, or the ATO kicks in again. In a similar vein, if the end of the tubing is lower than the water level in your ATO reservoir then water will continue to flow until the ATO water level either drops below the end of the tubing or the reservoir is empty.

Set up properly, there will likely be a small amount of back flow as the tubing empties, but shouldn't be more than a few ml and shouldn't affect the pump prime.

Think of it like having a bucket of water on the floor next to the display tank and a small pump with tubing going up of the edge of your display tank. You turn the pump on and it pumps water. Once you turn it off, all the water that is in the tubing drains back into the bucket. If the end of the tube is below the water surface in the tank, then a siphon starts and water keeps flowing until something happens to break the siphon.

Now if you have a similar setup but have the bucket on a shelf above the tank, once you turn off the pump, you have a siphon started and water will continue to flow from the bucket down to the display tank until something breaks the siphon.

So how do you stop this?

 

[Sleepydoc]

So how do you stop this?

Stop the back siphon? Simply make sure the end of the tube is not below the water line.

 

[Mav2]

Thank you