Rate of Water Evaporation

[lavoisier]

Is anyone aware of a chart or calculator that would give rates of evaporation in relation to humidity and temperature? I haven't seen anything result from my search of the forum and cannot find what I'm looking for by web search.

Barring that is there a "rule of thumb?"

 

[Randy Holmes-Farley Verified Community Expert]

Is anyone aware of a chart or calculator that would give rates of evaporation in relation to humidity and temperature? I haven't seen anything result from my search of the forum and cannot find what I'm looking for by web search.

Barring that is there a "rule of thumb?"

there likely won’t be such a thing as evaporation depends heavily on air flow as well, and that will happen even in a closed room where the tank is a different temp than the air.

 

[Randy Holmes-Farley Verified Community Expert]

Is anyone aware of a chart or calculator that would give rates of evaporation in relation to humidity and temperature? I haven't seen anything result from my search of the forum and cannot find what I'm looking for by web search.

Barring that is there a "rule of thumb?"

My impression is that most tanks evaporate 1-4% of the water volume daily. Not sure if that is useful for you though.

 

[Nano427]

If you google evaporation rate some info will come up, but if you’re trying to apply this to an aquarium I think that would be difficult. Too many variables such as turbulance and heat from lights like metal halides would make calculations difficult. Best bet would be to take an actual measurement of the evaporation.

 

[Mical]

There are a TON of variables (as mentioned above) air flow, temp, covered w/glass or screen, humidity in your home, etc.. The list goes on.

 

[lavoisier]

My impression is that most tanks evaporate 1-4% of the water volume daily. Not sure if that is useful for you though.

Yes, it is helpful. I am switching my peristaltic pump and after having calibrated it, I'll start with 1% and dial it in gradually.

 

[Goodair]

With my 90g, I can run through 5g in the ato in 2 days. This is with fans blowing on the surface. Winter, 5g can last 5 or 6 days. It will greatly vary with different tanks and the time in the year.

 

[Nano427]

Yes, it is helpful. I am switching my peristaltic pump and after having calibrated it, I'll start with 1% and dial it in gradually.

Can you add a float switch to it to prevent an overflow? Or at least enought room in the display/sump to prevent overflow? That would be my only concern using a peristaltic pump set at a constant rate

 

[lavoisier]

Can you add a float switch to it to prevent an overflow? Or at least enought room in the display/sump to prevent overflow? That would be my only concern using a peristaltic pump set at a constant rate

Thanks Nano, I appreciate your thought. The way my system is set up I do automatic water changes by running my skimmate wet with a float valve for my salt water mixing tank. I replace evaporation with the peristaltic pump set up on a 50g fresh water tank. The pump is controlled with my Apex and is programmed to shut off if conductivity drops to 34.5. I would then get an alert and check things out. The Apex salinity probe is not particularly accurate and gives plenty of false readings but it is a check on a major salinity shift.

Also, my tank is in the basement on a concrete floor so even with an overflow no damage to the house!