Wondering about salinity exchange in Icy's ATO.

DRC Archive General Saltwater Discussion
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[size=10pt][color=purple]After seeing Icy’s ATO I began to wonder about whether the Ro water would become salty over time and if the water would exchanged. I have been curious since I left and had time to think about it.

Now on this small of a scale it would not matter but it made me wonder.

Hot water rises
Cold water sinks

On this alone the water should drain out of the bottle as the warmer water moves up to take its place even with thought the bottle is under a vacuum, but…

Saltwater is more dense then Ro water.
Warm saltwater less dense then cold saltwater.

If Temp were the only force at work I would say over time it would defiantly switch. But there is the density of the water to consider. Warm saltwater would be less dense then cooler saltwater. But would they negate the action of the other? Would the Ro waters salinity switch over time?

This happens on a larger scale in the oceans. It actually effects the worlds climates. They say the little ice age was caused by a shift in the ocean currents because of a salinity change. It is claimed by some climatologist that because of global warming the glaciers will melt causing a large quantity of cold fresh water which will stop the current flow. If it were to stop it is hypothesized that since the warn tropic water would not flow north that Delaware would be a very cold place.

Icy a few questions ??
How long before the bottle emptys?

If you have the time could you…
Use the 2 liter bottle and record TDS
When the water is 3/4 finished being emptied, remove and test the TDS again.

There is 1 major flaw to this method; The TDS will rise somewhat if anything grows in the bottle. (Bacteria etc…)
I don’t think this will be too severe to alter the results too much. If the TDS starts at 0 and is a 5 ppm then I would suggest it does not happen or it could happen very very slowly. However if the results are a TDS of >50, I would say it is defiantly switching.

Any chance you could test this.

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Again I know the results of this happening will not have a negative effect on the tank since it is such a small amount of Fresh water. It is for my own knowledge and curiosity.

I put it on the forum vs. a pm because I figure some may be able to add insight I may not have seen and the rest will debate the existence of some kind of global warming :stuck_out_tongue:

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I don’t think it will happen the way you’re thinking. the ATO really works as a constant slow drip, it doesn’t wait for the tak water to drop an inch below the waterline then refill the tank.

I think any salt water that starts to creep up the ATO bottle would be immediately expelled as the fresh water continues it’s drip.

I imagine that any TDS reading would be a result of bacteria or small algae spores beginning to grow in the ATO bottle.

I think we would not only need to test for TDS but for salinity as well. If a positive on TDS but negligible on salinity we’d then have to consider coverong the soda bottle with something to block out light to prevent the growth of algae spores.

So Icy - do you own a lab coat yet?

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What’s TDS?

I don’t think its a drip. When the tube is exposed to the lower pressure of air instead of water it allows the water to come out of the bottle. The rest of the time the water is stuck in the bottle. Traveling up that tube is a pretty large pressure difference (6" of H2O) and doubt the saltwater could rise up it.

The reasons why I could see it wanting to travel up:
Everything wants to assimilate naturally.
Warmer saltwater (although the bottle would be pretty similar to tank I would suppose)

Reasons why it wouldn’t:
Density
6"+ of H2O water column

I vote it doesn’t change. If I’m wrong, you can put a check valve in, then I’ll be right again.

5

TDS = Total Dissolved Solids

I don’t necessarily mean a litteral drip, but whn the water level in the tanks mearly eeks below the tube a small amount of water will be released to raise it to the level of the tube. So it’s not topping off once a day at 1/3 of the bottle at a time but probably hundreds of times a day a drip at a time.

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Well my TDS meter is currently broke, but I could definatley test for salinity for you guys. Tonight I will fill a 2 liter an take before and 1/3 done salinities with the refractometer.

7

Even if it does rise into the ATO container, it still serves it’s purpose. As the salt rose in the container it would have to drop by an equal amount in the display, thereby lowerring the overall salinity. In that scenario, the water in the ATO being slightly salty would benefit the (lowered) salinity of the display. Basically, as long as you start out with fresh water in the ATO, it’s all good. EvIl GrIn

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I know it will serve its purpose, I was curious because water usually moves to equal itself in all facets. It self levels. It is viscus to pull water. High density will move to lower density and warm will move to cool. (As Ian stated) These things are what I am interested in. Yes it will not matter at all in this case or any other ATO, but it makes me wonder what will happen. Will it be enough to measure.

The ATO that Icy uses will not drip. As the tank water level evaporates it will drop below the water line which will cause the ATO device to quick Dump water into the tank till the vacuum is restored. It will happen many times per day as Craig suggested.

I meant to put salinity and TDS, it was late.

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[quote=“a1amap, post:8, topic:688”]
water usually moves to equal itself in all facets.[/quote]

Does this mean he could just remove the bottle and replace it to do a water change? Would the nitrates in the water equalize as well? Al, you come up with some good stuff! Curious to see where this one goes.

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[quote=“a1amap, post:8, topic:688”]
I was curious because water usually moves to equal itself in all facets. It self levels. It is viscus to pull water. High density will move to lower density and warm will move to cool. (As Ian stated)[/quote]

I won’t argue that water will self-level … assuming you meant with no external forces acting upon it.
Same for warm and cool water … no arguement. That would imply some sort of external force acting upon the body(ies). Or at least a non-uniform force. And I wouldn’t think the temperature delta between a reef tank and an ATO would be very significant.

As for density uniformity, that I would argue. Lacking turbidity or some other external factor/force, you will find density gradations in any settling pond. Else we wouldn’t have a use for settling ponds.

And if you want proof of this, at least anectdotal proof, just jump into the Schkulkyl river right at Boathouse Row, just above the Water Works. That’s a fine (although not for swimming) example of how a settling pond works.

  • $0.02
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[quote=“Jocephus, post:9, topic:688”]

[quote=“a1amap, post:8, topic:688”]
water usually moves to equal itself in all facets.[/quote]

Does this mean he could just remove the bottle and replace it to do a water change? Would the nitrates in the water equalize as well? Al, you come up with some good stuff! Curious to see where this one goes.[/quote]

Not sure that would work in a way that you would want. Let’s assume for a minute that
(1) you’re using clean S/W @ the same salinity as your tank/sump/system
(2) the amount of S/W is 10% of your tank/sump/system

Let’s compare two cases - Joe’s suggestion and the way most ppl do water changes:

Case 1 - Joe’s Idea

[code]What you, in effect, would be doing would be 1st adding 10% extra water to the system,
then taking that same amount out of the system.
Assume your nitrates are 20 parts per gallon (ppg) - not the right measurement,
but it makes the units easier to deal with.
Lets also assume that your system is 100 gallons. You would have:

100 @ 20 ppg = 2000 parts
10 @ 0 ppg = 0 parts
leaving you with 110G @ 18.18 ppg

Now you remove 10 gallons @ 18.18 ppg (or 181.8 parts), leaving you with 100 gallons @ 18.18 ppg[/code]

Case 2 - “Normal” water change

[code]Here, what you, in effect, would be doing would be 1st taking out 10% of the water in the system,
then adding that same amount into the system.
Again, assume your nitrates are 20 parts per gallon (ppg).
Lets also again assume that your system is 100 gallons. You would have:
Taking the water out:
100 @ 20 ppg = 2000 parts
-10 @ 20 ppg = 200 parts
leaving you with 90G @ 20 ppg (or 1800 parts)
Putting new S/W in:
90 @ 20 ppg = 1800 parts
+10 @ 20 ppg = 0 parts

leaving you with 100G @ 18 ppg (or 1800 parts)[/code]

Looking at this simplistic example, and assuming you could do a water change the way Joe surmised (and this assumes some mechanism for providing the mixing - or turbidity), you can deduce from the final numbers that this would not be an efficient mechanism.

Now I’m up to $0.04

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[quote=“ronert, post:10, topic:688”]

[quote=“a1amap, post:8, topic:688”]
I was curious because water usually moves to equal itself in all facets. It self levels. It is viscus to pull water. High density will move to lower density and warm will move to cool. (As Ian stated)[/quote]

I won’t argue that water will self-level … assuming you meant with no external forces acting upon it.
Same for warm and cool water … no arguement. That would imply some sort of external force acting upon the body(ies). Or at least a non-uniform force. And I wouldn’t think the temperature delta between a reef tank and an ATO would be very significant.

As for density uniformity, that I would argue. Lacking turbidity or some other external factor/force, you will find density gradations in any settling pond. Else we wouldn’t have a use for settling ponds.

And if you want proof of this, at least anectdotal proof, just jump into the Schkulkyl river right at Boathouse Row, just above the Water Works. That’s a fine (although not for swimming) example of how a settling pond works.

  • $0.02[/quote]

I agree with ronert. The lighter freshwater will more readily float on top of the denser salt water.

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[quote=“ronert, post:11, topic:688”]

[quote=“Jocephus, post:9, topic:688”]

[quote=“a1amap, post:8, topic:688”]
water usually moves to equal itself in all facets.[/quote]

Does this mean he could just remove the bottle and replace it to do a water change? Would the nitrates in the water equalize as well? Al, you come up with some good stuff! Curious to see where this one goes.[/quote]

Not sure that would work in a way that you would want. Let’s assume for a minute that
(1) you’re using clean S/W @ the same salinity as your tank/sump/system
(2) the amount of S/W is 10% of your tank/sump/system

Let’s compare two cases - Joe’s suggestion and the way most ppl do water changes:

Case 1 - Joe’s Idea

[code]What you, in effect, would be doing would be 1st adding 10% extra water to the system,
then taking that same amount out of the system.
Assume your nitrates are 20 parts per gallon (ppg) - not the right measurement,
but it makes the units easier to deal with.
Lets also assume that your system is 100 gallons. You would have:

100 @ 20 ppg = 2000 parts
10 @ 0 ppg = 0 parts
leaving you with 110G @ 18.18 ppg

Now you remove 10 gallons @ 18.18 ppg (or 181.8 parts), leaving you with 100 gallons @ 18.18 ppg[/code]

Case 2 - “Normal” water change

[code]Here, what you, in effect, would be doing would be 1st taking out 10% of the water in the system,
then adding that same amount into the system.
Again, assume your nitrates are 20 parts per gallon (ppg).
Lets also again assume that your system is 100 gallons. You would have:
Taking the water out:
100 @ 20 ppg = 2000 parts
-10 @ 20 ppg = 200 parts
leaving you with 90G @ 20 ppg (or 1800 parts)
Putting new S/W in:
90 @ 20 ppg = 1800 parts
+10 @ 20 ppg = 0 parts

leaving you with 100G @ 18 ppg (or 1800 parts)[/code]

Looking at this simplistic example, and assuming you could do a water change the way Joe surmised (and this assumes some mechanism for providing the mixing - or turbidity), you can deduce from the final numbers that this would not be an efficient mechanism.

Now I’m up to $0.04[/quote]

Again, I agree. If the ATO were to fully assimilate you are basically only adding the volume of the ATO to the system. Like adding a slightly larger sump. Then if you were to change it you would be changing this more diluted volume of water, where as a water change doesn’t add volume you replace the volume. (did that come out comprehensible?)

14

But would the temp change effect this? If density were the only issue I would tend to agree also. But warm always moves up and cold down. This is the basis of all ocean currents and weather patterns. [b]Will it have enough force to overcome the density issue? Will the water exchange salinity at the water separation line? Or will they balance?

As for density uniformity, that I would argue. Lacking turbidity or some other external factor/force, you will find density gradations in any settling pond. Else we wouldn't have a use for settling ponds.
External force? The temp would be that force.
I agree with ronert. The lighter freshwater will more readily float on top of the denser salt water.
True but would the force of the temp variance effectively have enough energy to overcome the density and force the switch?
Again, I agree. If the ATO were to fully assimilate you are basically only adding the volume of the ATO to the system. Like adding a slightly larger sump. Then if you were to change it you would be changing this more diluted volume of water, where as a water change doesn't add volume you replace the volume. (did that come out comprehensible?)
Not IMO. If the salt did "assimilate" there would be an initial dilution to the salinity but as water evaporated it would still balance so it would not act as a true sump till the water evaporated leaving the desired salinity. If you replaced it to do water changes (not recommended) your dilution suggestion would be correct IMO.
15
True but would the force of the temp variance effectively have enough energy to overcome the density and force the switch?

I don’t know. I don’t think there would be that much of a temperature variance. Initially yes, but I would assume that the ATO would reach the tank temp fairly quickly, as heat rises, I would think it would heat the ATO bottle up fairly quickly. It depends on room temp and how the ATO is setup.

For the sake of arguement I COULD dig up some thermodynamics and density equations and try to figure it out based on some real world numbers…But, I’m lazy.

Again, I agree. If the ATO were to fully assimilate you are basically only adding the volume of the ATO to the system. Like adding a slightly larger sump. Then if you were to change it you would be changing this more diluted volume of water, where as a water change doesn't add volume you replace the volume. (did that come out comprehensible?)
Not IMO. If the salt did "assimilate" there would be an initial dilution to the salinity but as water evaporated it would still balance so it would not act as a true sump till the water evaporated leaving the desired salinity. If you replaced it to do water changes (not recommended) your dilution suggestion would be correct IMO.

Yup, that was in regards to using the water bottle as water changing device.

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[quote=“a1amap, post:14, topic:688”]
But warm always moves up and cold down. This is the basis of all ocean currents and weather patterns.[/quote]
Not entirely true. You’re forgetting the gravitaional pull from the moon. Wave action produces significant turbidity.

[quote=“a1amap, post:14, topic:688”]

As for density uniformity, that I would argue. Lacking turbidity or some other external factor/force, you will find density gradations in any settling pond. Else we wouldn't have a use for settling ponds.
External force? The temp would be that force.[/quote] Keep in mind a 72 degree room temperature and an 80 degree tank does not give you a 10% difference in temperature, like a lot of people assume. That 8 degree difference would have to be measured on the Rankin scale (or converted to degrees C and used on a Kelvin scale). So what you are assuming to be a 10% delta in temperature is really somewhere between 2-3%. And, yes, while this temperature could be considered a forcing function, in this case I think trying to have a mouse push a dumptruck would be the best analogy I can think of to demonstrate how insignificant I think it would be. That's a gut feel, but you get the idea.
Not IMO. If the salt did "assimilate" there would be an initial dilution to the salinity but as water evaporated it would still balance so it would not act as a true sump till the water evaporated leaving the desired salinity. If you replaced it to do water changes (not recommended) your dilution suggestion would be correct IMO.
Umm, not sure, but I think you missed the point of my initial post, which was directed @ Joe's thoughts on water changes. I assumed he meant to use S/W, NOT RO (or fresh water). If you added RO and waited untill that volume evaporated, then you're right back to where you started ... just with more fish poo.
17

[quote=“ronert, post:16, topic:688”]
Umm, not sure, but I think you missed the point of my initial post, which was directed @ Joe’s thoughts on water changes. I assumed he meant to use S/W, NOT RO (or fresh water). If you added RO and waited untill that volume evaporated, then you’re right back to where you started … just with more fish poo.[/quote]

Actually, I meant adding the additional fresh RODI water, waiting for it to “assimilate”, then removing the (full) ATO container and replacing with slightly salty water. [glow=red,2,300]IF[/glow] the nutrients assimilate, then by Ted’s earlier 10 to 100g example, you could do a water change by simply adding an ATO, waiting a day, then removing it to be replaced with another [fly](allowing for the assimilated salts of course).[/fly]

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Or, I may be full of shite! HAHAHA Either way, good discussio n.

19

[quote=“a1amap, post:14, topic:688”]
But warm always moves up and cold down. This is the basis of all ocean currents and weather patterns.[/quote]

But think about the placement of the ATO - with the mouth of the bottle essentially sitting inside the hood, wouldn’t the heat from the lights moving up (as heat will always do) cause the water in the bottle to be warmer then the water in the tank?

Of course you have to factor in the temperature of the room, which would obviously be cooler, but which would be the dominating force? I would be interested to find out the temperature of the water in the ATO bottle at various points in the day - is it warmer in the afternoon which would prevent the tank water from assimilating - cooler in the evening allowing the waters to mix?