# Water evaporation



## BarryH (2 Dec 2019)

After many years with fancy goldfish I have started setting up a 60cm tank without a lid, just the light above.

What has really surprised me is the amount of water lost to evaporation. Never had to top up a a goldfish tank before but they all have covers on them.


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## dw1305 (2 Dec 2019)

Hi all, 





BarryH said:


> What has really surprised me is the amount of water lost to evaporation. Never had to top up a a goldfish tank before but they all have covers on them.


A lot of it is the heater in a tropical tank, it means the water is warmer than the room and more evaporation occurs.

cheers Darrel


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## DeepMetropolis (2 Dec 2019)

Having an open top tank is way cooler then those humidifiers.  

Verstuurd vanaf mijn SM-G920F met Tapatalk


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## MJQMJQ (3 Dec 2019)

BarryH said:


> After many years with fancy goldfish I have started setting up a 60cm tank without a lid, just the light above.
> 
> What has really surprised me is the amount of water lost to evaporation. Never had to top up a a goldfish tank before but they all have covers on them.


Same here,smaller tanks or tanks with more surface area lose water to evaporation more quickly.I lose abt 1-2 litres per week from my 32 litre tank but luckily my tap water TDS ia about 150-200.Watch yr TDS though


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## BarryH (3 Dec 2019)

MJQMJQ said:


> Same here,smaller tanks or tanks with more surface area lose water to evaporation more quickly.I lose abt 1-2 litres per week from my 32 litre tank but luckily my tap water TDS ia about 150-200.Watch yr TDS though


WOW! I'd never have guessed at that much. First open topped tank and I'm really surprised.


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## MJQMJQ (3 Dec 2019)

BarryH said:


> WOW! I'd never have guessed at that much. First open topped tank and I'm really surprised.


Because Im from singapore the temperature here is about 29 degrees celsius for indoor tanks.Relative humidity plays a part too!


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## dw1305 (3 Dec 2019)

Hi all, 





MJQMJQ said:


> Relative humidity plays a part too!


It does, if the air is fully saturated with water vapour, you don't get any evaporation.

In Singapore I assume it is always hot and humid, but this is quite important for us in the winter.

In the UK the atmosphere is pretty wet in the winter, but the air is relatively cool. When the 100% RH  air comes into the house it warms and the relative humidity falls. This allows it to pick up water from the fish tank etc. but when it reaches a cool surface (usually a window) the air cools and the water condenses.

If you live somewhere where the air is cooler and drier, you have even more of a difference.

The relationship between water content, temperature and relative humidity <"is non-linear">, but near enough to say that warm air can hold a lot more water than cold air.





cheers Darrel


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## Siege (3 Dec 2019)

What’s your temperature at @BarryH .

Should be at 22-23 degrees.


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## BarryH (3 Dec 2019)

Siege said:


> What’s your temperature at @BarryH .
> 
> Should be at 22-23 degrees.


It's at 23 currently but I need to cross check it with a glass thermometer as well. Using one of the digital at the minute.


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## MJQMJQ (4 Dec 2019)

dw1305 said:


> Hi all, It does, if the air is fully saturated with water vapour, you don't get any evaporation.
> 
> In Singapore I assume it is always hot and humid, but this is quite important for us in the winter.
> 
> ...



Now I get around 1 litre loss per week cos its wet season during dry season 1.5-2.Was thinking of getting a cover but the condensation will look ugly.


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## becks (4 Dec 2019)

People produce on average 1.2 litres of water through perspiration  per day.


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## zozo (4 Dec 2019)

And the draft in the house does a lot.  I loose between 2 and 3 litres per day over 2 open-top tanks. And the average humidity in the house is +/- 40%. But its an old drafty house build in 1920. 

In the winter its a 20°C tank temp and max 18.5°C room temp. Doesn't make much of a difference in volume that evaporates.


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## MJQMJQ (5 Dec 2019)

zozo said:


> And the draft in the house does a lot.  I loose between 2 and 3 litres per day over 2 open-top tanks. And the average humidity in the house is +/- 40%. But its an old drafty house build in 1920.
> 
> In the winter its a 20°C tank temp and max 18.5°C room temp. Doesn't make much of a difference in volume that evaporates.



Yep the draft removes moisture laden air.


becks said:


> People produce on average 1.2 litres of water through perspiration  per day.


@zozo this is what u need.A human humidifier.But on a side note that much perspiration?At what temperature?


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## dw1305 (5 Dec 2019)

Hi all, 





MJQMJQ said:


> But on a side note that much perspiration?


It is via breathing mainly.

cheers Darrel


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## MJQMJQ (5 Dec 2019)

dw1305 said:


> Hi all, It is via breathing mainly.
> 
> cheers Darrel



Oh yes oops.And since ure so free go look at my journal Imao


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## becks (5 Dec 2019)

Only knew that because humidity in dwellings is something I’ve been learning a lot about recently


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## ian_m (6 Dec 2019)

Slight off topic, if you have damp issues in your house, I would highly recommend these.
https://www.dehumidifiersuk.com/dio-ruby-dry-dh600-dessicant-dehumidifier-5-5-litre-extraction.html

They do not use a compressor so are virtually silent, so can be installed in living spaces without keeping you awake at night. Also work down to 0'C (unlike compressor dehumidifiers) so can be used in outside sheds/garages etc.

My mate had severe issues with damp in his house, basically caused by humid air from tiny kitchen passing through his lounge and up the stair case, which enters into the lounge, and condensing as water on upstairs windows. Tried a curtain round the stairs in the lounge, did work well stopping the moisture but looked naff and was always not "closed". Installed one of these dehumidifiers on upstairs landing. It only lasted a day before it stopped as water compartment was full !!!. Ended up plumbing it in so water continuously drained to outside gutter. Moisture issue was eventually 100% solved (and dehumidifier sold) due to kitchen extension moving the cooker further away from the door along with decent extractor cooker hood, preventing moisture getting out in the first place and replacement double glazing upstairs all with trickle vents.


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## becks (6 Dec 2019)

I think a better alternative to a dehumidifier is installing PIV, something like Naurie drimaster. People are concerned about pushing cold air from the loft space into the house and believing it’s going to make the house cold.  They are great and drier air is cheaper to warm up than humid air. 

the drimaster is about 18w irc, they do one with a heated element, but I would not really use one.


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## BarryH (22 Jan 2020)

Back on the water evaporation again, has anyone made glass or clear plastic covers for their open topped tanks?


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## Simon Cole (22 Jan 2020)

I prefer glass sheet to plastic. It will not scratch or discolor and can be cleaned quickly with distilled vinegar. Snails will also find the underside quite appealing, and the top makes a nice place to put a cup pf tea.


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## Aqua sobriquet (22 Jan 2020)

becks said:


> I think a better alternative to a dehumidifier is installing PIV, something like Naurie drimaster. People are concerned about pushing cold air from the loft space into the house and believing it’s going to make the house cold.  They are great and drier air is cheaper to warm up than humid air.
> 
> the drimaster is about 18w irc, they do one with a heated element, but I would not really use one.



That’s interesting. We do suffer with damp and are currently using a dehumidifier. We had a Mitsubishi but that failed after about four years so we’re now using a Ruby Dry. Do you use a PIV? I didn’t realise that they were so reasonably priced. Just wondering how effective they really are and how much the installation is going to cost.


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## ian_m (22 Jan 2020)

Aqua sobriquet said:


> Do you use a PIV? I didn’t realise that they were so reasonably priced. Just wondering how effective they really are and how much the installation is going to cost.


My friend had one fitted, as he suffered from severe condensation in his loft each spring and autumn, possibly attributed to damp house. Was fitted by a "condensation consultant" to try and "dry" the house but made no difference as in the end the PIV just provides more house air circulation.

Eventually solved by replacement of double glazing all now with air trickle vents and a Ruby Dry dehumidifier installed in the loft. Eventually all solved when a builder (doing other work) spotted that the tops of the walls, in the loft, were not capped under the gables and in his words and experience the condensation was all due to low loft height (roof angle was very shallow, condensation not seen in steeper roofed properties) and incorrectly capped brickwork. So he sorted it and condensation in loft went away, Ruby Dry was sold and condensation was no longer an issue.


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## Majsa (22 Jan 2020)

BarryH said:


> Back on the water evaporation again, has anyone made glass or clear plastic covers for their open topped tanks?



I got tired of evaporation and fitted an ADA glass cover to my standard 30x60 cm tank. The clips were a bit too wide so put a small piece of air tube in between, can't really see it. 
The condensation you see is at room temperature of 19 degrees Celsius vs. tank temp of 22. Not that pretty, but it works. It took a bit fine tuning (surface level & movement) but the limnobium is doing fine.


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## becks (22 Jan 2020)

Aqua sobriquet said:


> That’s interesting. We do suffer with damp and are currently using a dehumidifier. We had a Mitsubishi but that failed after about four years so we’re now using a Ruby Dry. Do you use a PIV? I didn’t realise that they were so reasonably priced. Just wondering how effective they really are and how much the installation is going to cost.



yes they are brilliant, I have one fitted and I would suggest them to anyone who suffers from humidity issues (if it’s not due to a defect) Ian demonstrated a lack of understanding on the subject as that house clearly suffered from a building defect. Google nuaire piv and see how many people say how effective they are.  

They are much more effective than a dehumidifier.  Just googling it will show you experiences of people who have owned both.  

A lot of social housing will install these when tenants complain about damp and condensation issues which is predominantly caused by their lifestyle, fitting the PIV forces fresh air into the house which pushes out the damp humid internal air. Even when the outside humidity is high, when that enters your house and warms up the humidity will reduce.

plus your notice better internal air quality.


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## BarryH (22 Jan 2020)

Thanks for the help Majsa, really appreciated. The Limnobium looks to be in really great colour. I was just worried my original post was getting a bit lost among the threads about dehumidifiers.


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