# Evaporation?



## baron von bubba (25 Apr 2009)

hi,
i have a 240l open top tank and at the moment its probably losing around 10l's a week to evaporation.

i'm wandering if i should be using RO water to top up? as if i top up with tap water or just wait and refill at next water change, wont the gh and kh steadily increase? 
my tap water is moderatly hard with a kh of 8


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## George Farmer (25 Apr 2009)

By topping up with tap water the mineral content of the aquarium water will gradually increase, like you suggest.

Large (50%+ every 2 weeks or more frequent) water changes should prevent excess an excess build-up.

If large water changes aren't an option then topping with RO may be necessary, although most plants and fish will readily adapt to a gradually increasing hardness, within reason.


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## baron von bubba (25 Apr 2009)

i've just gone from two 50% changes per week down to one 50% weekly water change.

so if i stick to this routine, evaporation and the resulting tds increase wont be and issue? thats good to know!

thanks


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## chris1004 (26 Apr 2009)

10 litres a week!!!!!!!!   

Wow thats serious evapouration.

I've never had an opentopped tank and didn't realise that they could lose that much water. Thats a serious eye opener for me, where does it all go? You must suffer from a lot of condensation or use a room dehumidifier. I don't think that I will ever look at open topped tanks in the same light again.


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## Dolly Sprint 16v (26 Apr 2009)

chris1004 said:
			
		

> 10 litres a week!!!!!!!!
> 
> Wow thats serious evapouration.
> 
> I've never had an opentopped tank and didn't realise that they could lose that much water. Thats a serious eye opener for me, where does it all go? You must suffer from a lot of condensation or use a room dehumidifier. I don't think that I will ever look at open topped tanks in the same light again.



Thats over 2.5 gallons per week - I would say that there is a leak somewhere :!:  :!:, if you are concerned regarding the amount of fluid loss, buy some clear perspex and cut it to suit your top and place in position - that should reduce some  evaporation. 

Regards
Paul.


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## a1Matt (26 Apr 2009)

Rather than a leak, IMHO I'd hazard a guess that the Barons lights are close to the water surface, that would increase levels of evaporation.


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## GreenNeedle (26 Apr 2009)

I lose about 10Ltrs a week from my 125Ltr.  Its not that much really.  and my lights are 15" above the water!!!

I think its more about the difference in temperature of the water and the ambient temperature.

AC


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## Dave Spencer (26 Apr 2009)

I add about 10l per week to my open topped 240l, and the walls in the house are bone dry. 8) I do have a fair amount of surface disturbance, which probably increases the rate of evaporation.

Dave.


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## Superman (26 Apr 2009)

I lose what seems to be 1ltr a day in evaporation, when I'm away for the weekend the livingroom windows are covered in condensation.
It doesn't help I've got a fair bit of surface movement and the lights are closeish to the surface.
If I keep on top of it each day it's not too bad, but say if I left it for a week then the water would be down to the spray bar.


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## baron von bubba (26 Apr 2009)

do you guys top up with RO or are you not worried about that?

i don't get condensation on any window, patio door is often open tho.

i guess air humidity/flow and the water/air temps would be the main factors driving evaporation.
ah, and surface area!

from what you guys say tho my loss is pretty normal.


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## Superman (26 Apr 2009)

I just use the council's finest tap water.


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## JamesM (26 Apr 2009)

Yup, same here, I lose around half a litre a day and top up with council pop.


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## GreenNeedle (26 Apr 2009)

A jug or 2 of tap water for me too.  I don't get condensation in my house from it.  Maybe my house temp is lower?  Around the 17-18ÂºC mark.  I also have those little open/close slit thingamys at the top of the windows which are open all year round.  I believe that may be a key factor to the no condensation.

AC


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## Themuleous (10 May 2009)

I use Ro to top up my 4ft, but only so I don't get an hardness built up.  But that is easily sorted by a bigger than normal WC every so often.

I must loose around 10lt from the tank all told, walls don't seem to be affected.  Condensation only happens when its cold outside.

Sam


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## baron von bubba (1 Jun 2009)

i've noticed over the course of a two week period another down side to evaporation, the spray bar disturbs the water more as water levels drop so co2 levels therefore decrease as the week goes on!

so daily top ups for me now!

kinda obvious really tho i guess, it appears i'm a little slow on the uptake sometimes!!! :0/


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## Themuleous (2 Jun 2009)

Tell me about it!

viewtopic.php?f=21&t=5804

Sam


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## baron von bubba (2 Jun 2009)

Themuleous said:
			
		

> Tell me about it!
> 
> viewtopic.php?f=21&t=5804
> 
> Sam



Has your tank recovered from that slight oversight yet?

Because i'm still fiddlin daily with my set up, tweaking and checking, i managed to avoid having any problems from it happenin, thankfully!

Remember what doesn't kill us only makes us stronger........or so they say.
I've always thought maybe they didnt consider polio tho!


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## Themuleous (2 Jun 2009)

Yeh, the ottos and snails sorted the brown algae issue.  I'll be ripping the tank apart again soon so it doesn't really matter anyway!



			
				baron von bubba said:
			
		

> Remember what doesn't kill us only makes us stronger........or so they say.
> I've always thought maybe they didnt consider polio tho!



Yeh, what about HIV?  That doesn't kill you per se, other things do!

Sam


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## mattyc (1 Jul 2009)

look at this it explains a bit more what causes evaporation http://en.wikipedia.org/wiki/Evaporation

Matt


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## AdAndrews (1 Jul 2009)

im happy to just top up my tank, but always think surely evaporation isnt good for a room, the moisture levels and what have you. does it create damp, and has anyone had bad experiences of damage to their room becuase of the evaporation from tanks?


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## davidcmadrid (15 Jul 2009)

chris1004 said:
			
		

> 10 litres a week!!!!!!!!
> 
> Wow thats serious evapouration.
> 
> I've never had an opentopped tank and didn't realise that they could lose that much water. Thats a serious eye opener for me, where does it all go? You must suffer from a lot of condensation or use a room dehumidifier. I don't think that I will ever look at open topped tanks in the same light again.




I lose the same or more here in Spain with all the heaters plugged out in the summer.


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