Advice for "aquarium" need (cooling water / technical setup / no fish)

[niels123]

It will be interesting to see how it all works in the end.

ZombieEngineers remark is technically correct. However, the second tank (without coil) is so small that adding a pump there will be extremely impractical, effectively impossible. Therefore I choose the Eheim 2400, which can be positioned outside the water. It is outside the second tank. I could put it in air, but I just placed it in the big tank because of space convenience

 

[MnFish1]

Second issue is the antivibration feet of the Eheim pumps. Shown is the bottom plate of the Eheim 2100 with one rubber foot. The seller told me that you must insert them into the grooves of the plastic plate using a rotating motion. However, the diameter of top round part of the feet that is supposed to send up "above" the grooves is far too wide. Therefore the feet don't seem to fit and I can't get them into the grooves. Does someone has experience with this system and any tips or suggestions?

Assuming they are the correct "feet" you put them sideways (the top nipple) into the plastic and you may have to use something like a pliers to pull it through - when you stretch the rubber - it gets smaller and eventually pops through.

 

[MnFish1]

ZombieEngineers remark is technically correct. However, the second tank (without coil) is so small that adding a pump there will be extremely impractical, effectively impossible. Therefore I choose the Eheim 2400, which can be positioned outside the water. It is outside the second tank. I could put it in air, but I just placed it in the big tank because of space convenience

What I'm not totally understanding is - you have a coil in the large tank - which has cold water from a chiller - this will keep the water in the coil 'cold' (hopefully). My curiosity is how are you going to cool the water in the small tank? (This has always been my question)

 

[niels123]

What I'm not totally understanding is - you have a coil in the large tank - which has cold water from a chiller - this will keep the water in the coil 'cold' (hopefully). My curiosity is how are you going to cool the water in the small tank? (This has always been my question)

For thought purpose you can place the Eheim 2400 outside of any tank on a dry bench. The Eheim 2400 has 2 tube connectors so you can place it outside the tank. A tube runs from the 2400 pump to the coil placed inside cold water. Then on the other end of the coil a second tube is connected. This tube runs to the second thank. Then from that second tank a third tube is connected with the other end connected directly to the Eheim 2400.

So the tank that you need to cool "externally" only has the ends of 2 tubes in it, making it possible to use a 1 L container without much issues.

 

[ZombieEngineer]

It will be interesting to see how it all works in the end.

It's a matter of physics. Let's say for example the small tank starts at 100 degrees and the large tank starts at 60 degrees

If you have a pump in one side, the water entering the coil is exactly the temperature of the tank it is pulled from and then that temperature interacts with the other tank through the coil. The small tanks coil reacts with a 40 degree temperature delta. Since the large tank can stay at 60 degrees, this cooling effect remains constant.

If you have coils in both sides, the coil on one side cools some of the water to approach the temperature of the tank but can never reach it. So what actually happens is the small tank heats the previously 60 degree water to something less than 100 degrees, probably 80, then that water returns and cools down to more than 60 degrees, probably 70, then returns and heats up to 85 then returns and cools to 73 and then repeats this process until a sort of in between equilibrium is reached that likely ends up with the water cooling the small tank being 25% hotter than the cooling tank.

 

[niels123]

It's a matter of physics. Let's say for example the small tank starts at 100 degrees and the large tank starts at 60 degrees

If you have a pump in one side, the water entering the coil is exactly the temperature of the tank it is pulled from and then that temperature interacts with the other tank through the coil. The small tanks coil reacts with a 40 degree temperature delta. Since the large tank can stay at 60 degrees, this cooling effect remains constant.

If you have coils in both sides, the coil on one side cools some of the water to approach the temperature of the tank but can never reach it. So what actually happens is the small tank heats the previously 60 degree water to something less than 100 degrees, probably 80, then that water returns and cools down to more than 60 degrees, probably 70, then returns and heats up to 85 then returns and cools to 73 and then repeats this process until a sort of in between equilibrium is reached that likely ends up with the water cooling the small tank being 25% hotter than the cooling tank.

I don't think you have the correct setup in your head. There is only one coil. It is in actively cooled water (with a chiller). The small tank has no coil. The entire contents of the small tank is constantly circulated through the coil. The Eheim 2400 can do 2400 L/h, but you never get anything close to that figure because I use 12mm tube of significant length and 2 meters up via the ceiling. So let's say you loose 95% of your capacity you will still have 120 L / h. If the small tank is 2 liters its entire contents will run through the copper spiral every 60 seconds. It should very quickly cool down to the temperature of the big tank + maybe 1-2C.

 

[MnFish1]

For thought purpose you can place the Eheim 2400 outside of any tank on a dry bench. The Eheim 2400 has 2 tube connectors so you can place it outside the tank. A tube runs from the 2400 pump to the coil placed inside cold water. Then on the other end of the coil a second tube is connected. This tube runs to the second thank. Then from that second tank a third tube is connected with the other end connected directly to the Eheim 2400.

So the tank that you need to cool "externally" only has the ends of 2 tubes in it, making it possible to use a 1 L container without much issues.

Yes - This is what I thought you were doing. My comment about 2 coils - I think you and @ZombieEngineer misunderstood. All I meant is that my GUESS is that to get the water as cold as you want it to be, (in the small tank) you will need a larger surface area of 'copper' in the smaller tank. But - thats also why I said 'it will be interesting to see how it turns out'.

 

[niels123]

Yes - This is what I thought you were doing. My comment about 2 coils - I think you and @ZombieEngineer misunderstood. All I meant is that my GUESS is that to get the water as cold as you want it to be, (in the small tank) you will need a larger surface area of 'copper' in the smaller tank. But - thats also why I said 'it will be interesting to see how it turns out'.

Just mixing its contents will always be more effective than cooling it via a heat exchanger ;-)

 

[MnFish1]

I don't think you have the correct setup in your head. There is only one coil. It is in actively cooled water (with a chiller). The small tank has no coil. The entire contents of the small tank is constantly circulated through the coil. The Eheim 2400 can do 2400 L/h, but you never get anything close to that figure because I use 12mm tube of significant length and 2 meters up via the ceiling. So let's say you loose 95% of your capacity you will still have 120 L / h. If the small tank is 2 liters its entire contents will run through the copper spiral every 60 seconds. It should very quickly cool down to the temperature of the big tank + maybe 1-2C.

AHHHHHHHHHHH - SO THERE IS NOT A 'CLOSED LOOP', i.e. a continuous length of 12 mm tubing. Instead you will be sucking water from the 1 liter tank - through the coil in the cold tank - and then putting it back into the small tank via the same pump? I was thinking (and recommending) - the you use a piece of copper - pumped into the coil into the cold water - which then (the tubing) would run through the small tank - cooling the water - and then be returned though the tubing back into the pump inlet. So - no water is coming out. Instead, the cold water in the copper tubing going through the small tank - would be cooling that water.

 

[niels123]

AHHHHHHHHHHH - SO THERE IS NOT A 'CLOSED LOOP', i.e. a continuous length of 12 mm tubing. Instead you will be sucking water from the 1 liter tank - through the coil in the cold tank - and then putting it back into the small tank via the same pump? I was thinking (and recommending) - the you use a piece of copper - pumped into the coil into the cold water - which then (the tubing) would run through the small tank - cooling the water - and then be returned though the tubing back into the pump inlet. So - no water is coming out. Instead, the cold water in the copper tubing going through the small tank - would be cooling that water.

Maybe this schematic drawing helps.

 

[MnFish1]

Just mixing its contents will always be more effective than cooling it via a heat exchanger ;-)

It may be more efficient - but - I wonder if you will have a lot of splashing, etc - in the small container - and the flow will be considerable. But - it will be interesting to see.

 

[MnFish1]

Maybe this schematic drawing helps.

Yes it does. My idea was exactly the same - except using a small coil in the tank - so there is not water flowing freely. I.e.

Maybe this schematic drawing helps.

This is what I was thinking - my coil did not draw well

 

[SteveMM62Reef]

Vinyl tubing is a good insulator. PVC is also a good insulator. Glass Pipe would be a good conductor. I believe you can even get the U bends on Amazon. BTW Ehiem pumps are way up there on the amount of heat produced verses water movement. I had to use my Calcium Reactor Pump as an emergency return pump. Pushed my temperature way up verses the bigger TAAM RIO, that failed.

 

[niels123]

Yes it does. My idea was exactly the same - except using a small coil in the tank - so there is not water flowing freely. I.e.

This is what I was thinking - my coil did not draw well

The thing is: the small tank is a small tank for a reason ;-) There is no room for a copper coil. Think: volume of a small pan (but made of plastic). If there is too much flow / splashing I can restrict the flow with the valves fitted in the tubing.

Also: your drawing is a completely closed system. I think it will be a challenge to get the air removed from the system. A typical example of a closed water-system is the central heating system in many (European) homes. There are tiny valves on various places you can open to let the air out. I've seen that these pumps are designed to pump water, not air. When there is air that you are pumping around you are reducing your cooling power and probably making a lot of noise too.

 

[MnFish1]

Maybe this schematic drawing helps.

OK I looked at this again - and I think you might want to re-think a couple things.
Perhaps you have drawn your arrows incorrectly - BUT - assuming I'm looking at it correctly, you're planning to 'suck water through from the small tank through the coil to the pump. Then the pump will pump the cold water back into the small tank.

1. You will need a fairly large volume to prime the pump - what is going to get the water flowing?
2. When you turn the pump off - the water from the large tank will siphon out - at least the way you have it drawn. If you have the small tank higher than the large tank, this will not be an issue.

I would recommend that the outlet of your pump goes directly to the coil then over to the small tank and then the outflow from the small tank will go into the intake of your pump - assuming you're staying with this design. This will help with 2 things 1. any heating from the pump will be cooled by the coil and 2 you will need less volume to prime the pump. It remains unclear what will happen when the pump is shut off - and how you will prime it when you start it - and if when you start it there will be an overflow, etc - depending on the volume of water that is 'inside' the pipe.

 

[MnFish1]

The thing is: the small tank is a small tank for a reason ;-) There is no room for a copper coil. Think: volume of a small pan (but made of plastic). If there is too much flow / splashing I can restrict the flow with the valves fitted in the tubing.

Also: your drawing is a completely closed system. I think it will be a challenge to get the air removed from the system. A typical example of a closed water-system is the central heating system in many (European) homes. There are tiny valves on various places you can open to let the air out. I've seen that these pumps are designed to pump water, not air. When there is air that you are pumping around you are reducing your cooling power and probably making a lot of noise too.

I wasn't advocating what I was saying - I was just drawing what I thought you were doing from weeks ago. In re-looking at it - I would put the pump in the large tank, then any heating from the pump will be taken care of. And I would have the outlet of the pump go directly into the coil - and then into the small tank - seems like this would be the most efficient? I think without doing this - you are also going to have issues priming the pump (i.e. getting air out of the lines.

 

[niels123]

I wasn't advocating what I was saying - I was just drawing what I thought you were doing from weeks ago. In re-looking at it - I would put the pump in the large tank, then any heating from the pump will be taken care of. And I would have the outlet of the pump go directly into the coil - and then into the small tank - seems like this would be the most efficient? I think without doing this - you are also going to have issues priming the pump (i.e. getting air out of the lines.

Actually I am putting the pump in the large tank. However, because I thought it would be confusing I just placed it outside the tank in the drawing to show the principle. The operation is the same with this pump model.

My 2 (silly) issues are the adapter that connects the 19mm tube to the 12mm tube. The 12mm tube comes off from the adapter far too easy.

And I bought the pumps new with the rubber feet included in the package. But I can't get them on. The top part of the feet is far too big to be pushed through the slid of the plastic pump housing. I have tried pliers but it still seems impossible.

 

[Dan_P]

Hopefully we will soon find out. I think it should be possible, The cooler is already quite big and the bath I need to cool has a tiny volume (1 - 2 L) compared to my main tank (it will contain about 50 L of water).

What I am curious about: do most aquarium users that use these kind of coolers have a valves fitted inside the tubing so you can disconnect the cooler without flooding the floor?

I don’t know how aquarist plumb there systems. I would use quick disconnects rather than valves. I think some systems use a titanium coil (and a nontoxic heat exchange fluid) submersed in the aquarium water to avoid putting aquarium water inside the chiller.

 

[niels123]

OK I looked at this again - and I think you might want to re-think a couple things.
Perhaps you have drawn your arrows incorrectly - BUT - assuming I'm looking at it correctly, you're planning to 'suck water through from the small tank through the coil to the pump. Then the pump will pump the cold water back into the small tank.

1. You will need a fairly large volume to prime the pump - what is going to get the water flowing?
2. When you turn the pump off - the water from the large tank will siphon out - at least the way you have it drawn. If you have the small tank higher than the large tank, this will not be an issue.

I would recommend that the outlet of your pump goes directly to the coil then over to the small tank and then the outflow from the small tank will go into the intake of your pump - assuming you're staying with this design. This will help with 2 things 1. any heating from the pump will be cooled by the coil and 2 you will need less volume to prime the pump. It remains unclear what will happen when the pump is shut off - and how you will prime it when you start it - and if when you start it there will be an overflow, etc - depending on the volume of water that is 'inside' the pipe.

The 'order' of things (pump - coil - small tank) is a good one. I am not sure how I connected it, but it is fairly easy to swap some tubing.

Yes the small tank needs to be big enough to hold its own water volume + the tube contents. However, I have valves installed, so I can easily close those, take an empty beaker and empty the tubing in it (or in the drain).

There is no actual mixing of the water between the tanks. I could add a food coloring to the big tank and the water in the small tank will remain colorless.

 

[ZombieEngineer]

I don't think you have the correct setup in your head. There is only one coil. It is in actively cooled water (with a chiller). The small tank has no coil. The entire contents of the small tank is constantly circulated through the coil. The Eheim 2400 can do 2400 L/h, but you never get anything close to that figure because I use 12mm tube of significant length and 2 meters up via the ceiling. So let's say you loose 95% of your capacity you will still have 120 L / h. If the small tank is 2 liters its entire contents will run through the copper spiral every 60 seconds. It should very quickly cool down to the temperature of the big tank + maybe 1-2C.

Same physics apply but cooling hot vs warming cold. I was explaining the process of why 1 coil was preferred to 2.