# Lime scale left by evaporation



## ale36 (9 Jan 2013)

I have an Arcadia Arc tank that a week after water change I have lost about 3-5 cm of water due to evaporation and it always leaves lime scale lines making it unpleasant to look at.
How do you guys avoid the lime scale left by evaporation of hard tap water ruining the nice look of your tanks? 
especially in open tops?
Any tips, advice or recommendations?


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## Nathaniel Whiteside (9 Jan 2013)

Get a glass top for it. You cant really prevent it otherwise.


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## SmallestFrog (9 Jan 2013)

I have the same tank, and the same problem. I use a razor blade scraper to remove thick build up of limescale, but most of the time I've found some water and a sponge washing up pad does the trick.


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## nayr88 (9 Jan 2013)

Would a surface skimmer attachment on your filter help this?
Would I have much effect on co2 levels?


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## tim (9 Jan 2013)

Top it up daily when u add ferts or feed fish or every couple of days


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## Iain Sutherland (9 Jan 2013)

tim said:


> Top it up daily when u add ferts or feed fish or every couple of days​


that and give it a wipe with an algae pad every few days to stop it building up.
Also the only good use for 'PH down' is to remove built up scale.


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## nayr88 (9 Jan 2013)

Does topping up evaporated water not increase The hardness of the water?


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## ale36 (9 Jan 2013)

Whitey89 said:


> Get a glass top for it. You cant really prevent it otherwise.


 I do have a glass cover that come with it



SmallestFrog said:


> I have the same tank, and the same problem. I use a razor blade scraper to remove thick build up of limescale, but most of the time I've found some water and a sponge washing up pad does the trick


 The Cleaning of it is not an issue, It's was more about preventing it from happening.




nayr88 said:


> Would a surface skimmer attachment on your filter help this? Would I have much effect on co2 levels?


I have an air powered under gavel filter



tim said:


> Top it up daily when u add ferts or feed fish or every couple of days


 
this isn't a planted tank "Yet"  when topping up should i use tap water or would you recommend topping up with RO? i belive i was once told to never top evaporated water with tap water instead to do a water change a fill it back up?


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## tim (9 Jan 2013)

I use tap dechlorinated the night before on most tanks top up my shrimp tanks with ro who told you not to top up evaporated water


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## ale36 (9 Jan 2013)

tim said:


> I use tap dechlorinated the night before on most tanks top up my shrimp tanks with ro who told you not to top up evaporated water


i can't remember who told me maybe i read it some where, all i remember is that i that due to the water evaporating it always leave all the nutrients and minerals behind so by topping with tap water you would be increasing what was left behind including salts.


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## Dan Crawford (9 Jan 2013)

As the water evaporates the hardness rises. Well, actually it doesn't rise but the calcium doesn't evaporate with the water leaving the same amount of calcium but in less water, this shows a rise in hardness. Does that make sense?

The "limescale" you see on the glass are calcium deposits, the only way to avoid these is to use water with less calcium in it, RO or bottled water. Surface agitation encourages evaporation so try and avoid that if your fish are happy with a still surface.


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## tim (9 Jan 2013)

ale36 said:


> i can't remember who told me maybe i read it some where, all i remember is that i that due to the water evaporating it always leave all the nutrients and minerals behind so by topping with tap water you would be increasing what was left behind including salts.


ah I see that's why ro is used for top ups in marine tanks 





Dan Crawford said:


> As the water evaporates the hardness rises. Well, actually it doesn't rise but the calcium doesn't evaporate with the water leaving the same amount of calcium but in less water, this shows a rise in hardness. Does that make sense?
> 
> The "limescale" you see on the glass are calcium deposits, the only way to avoid these is to use water with less calcium in it, RO or bottled water. Surface agitation encourages evaporation so try and avoid that if your fish are happy with a still surface.


Not something I would have thought off excellent explanation dan


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## nayr88 (9 Jan 2013)

Dan Crawford said:


> As the water evaporates the hardness rises. Well, actually it doesn't rise but the calcium doesn't evaporate with the water leaving the same amount of calcium but in less water, this shows a rise in hardness. Does that make sense?
> 
> The "limescale" you see on the glass are calcium deposits, the only way to avoid these is to use water with less calcium in it, RO or bottled water. Surface agitation encourages evaporation so try and avoid that if your fish are happy with a still surface.



Exactly what I thought. Good break down though I really struggle with wording thins like this haha.

I'd consider an RO system to rid me if the build up, it looks so nasty and even with wiping it off its just an endless battle.


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## dw1305 (9 Jan 2013)

Hi all,


> Does topping up evaporated water not increase The hardness of the water?


It depends upon the water you use to top up with. The water that evaporates is pure H2O, so you have the same volume of salts in a smaller volume of "water" and the remaining tank water has higher conductivity.

If the salts present were carbonates you will have harder water as well. The lime scale forms just above the waters surface. As the H2O evaporates the concentration of salts rises until they exceed the solubility for each salt and begin to precipitate out of solution. Calcium carbonate is relatively insoluble, so it is one of the first salts to precipitate out of solution.

If you top up with RO you will just replace the H2O that has evaporated, but if you use supply with salts in it (like most tap water) the concentration of salts in the tank will rise over time.

cheers Darrel


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## ale36 (9 Jan 2013)

dw1305 said:


> It depends upon the water you use to top up with. The water that evaporates is pure H2O, so you have the same volume of salts in a smaller volume of "water" and the remaining tank water has higher conductivity. If the salts present were carbonates you will have harder water as well. The lime scale forms just above the waters surface. As the H2O evaporates the concentration of salts rises until they exceed the solubility for each salt and begin to precipitate out of solution. Calcium carbonate is relatively insoluble, so it is one of the first salts to precipitate out of solution. If you top up with RO you will just replace the H2O that has evaporated, but if you use supply with salts in it (like most tap water) the concentration of salts in the tank will rise over time. cheers Darrel


 
That is pretty much what i was told/read, so should i use RO water to top-up the tank? would mixing say 50/50 RO/Tap on water change help to minimise the scale left behind? i have never used RO water before


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## dw1305 (9 Jan 2013)

Hi all,
I see I managed to repeat Dan and Ale36's posts and clutter the thread up, so with apologies for that. I should have said that increased carbonate levels would raise dKH and increased calcium levels dGH, but as calcium carbonate is both the most common carbonate and the least soluble one, evaporation will definitely increase both dGH and dKH.





> so should i use RO water to top-up the tank? would mixing say 50/50 RO/Tap on water change help to minimise the scale left behind? i have never used RO water before


 I would top up with 100% RO (I actually use rain-water, but for the same reasons). Whether 50:50 tap/RO works depends upon how hard your tap water is, because it isn't a planted tank levels of all salts will increase over time, until you dilute them with your next water change.

cheers Darrel


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## Nathaniel Whiteside (9 Jan 2013)

dw1305 said:


> Hi all,
> I see I managed to repeat Dan and Ale36's posts and clutter the thread up, so with apologies for that. I should have said that increased carbonate levels would raise dKH and increased calcium levels dGH, but as calcium carbonate is both the most common carbonate and the least soluble one, evaporation will definitely increase both dGH and dKH. I would top up with 100% RO (I actually use rain-water, but for the same reasons). Whether 50:50 tap/RO works depends upon how hard your tap water is, because it isn't a planted tank levels of all salts will increase over time, until you dilute them with your next water change.
> 
> cheers Darrel




The first person who mentions any one of your comprehensive replies and clutter in the same sentence, Darrel,  deserves to be shot.


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## Ady34 (9 Jan 2013)

Whitey89 said:


> The first person who mentions any one of your comprehensive replies and clutter in the same sentence, Darrel, deserves to be shot.


....apart from Darrel himself of course!


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## ale36 (9 Jan 2013)

looks like I'm going to have to know on my neighbours door and as for permission to tap into their gutter to collect some rain water


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## vauxhallmark (25 Jan 2013)

Topping up with ro would be ideal. Topping up with tap (or whatever you use to fill the tank) shouldn't do any damage if you are doing a 50% change weekly. Vinegar on a kitchen towel will also get rid of the limescale - I use it for the acrylic lens of my Arcadia luminaire. I think your tank is glass, but with rounded corners; a razor blade should be fine, but the corners will be tricky, and you will create zero scratches if you use vinegar (you can moisten the towel with it and wrap it round the top of the tank for a few minutes while the water level's down for a water change. 

Mark


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