how complex is it to calculate the evaporation rate of a typical medium size reef tank?

[KStatefan]

i

i thought more water evaporates in summer

It might be for you. Here it is humid in the summer and during the winter it gets very dry room temperature basically stays the same.

 

[Reeferbadness]

Get an Automatic Top Off system (Red Sea or Tunz are two good ones) and forget the math and variables and keep your tank stable. The end.

 

[Randy Holmes-Farley]

i

i thought more water evaporates in summer

Not in my house. Air is humid in summer and very dry in winter.

 

[Garf]

Here in the UK the air is full of water, most of the year. Our grass is nice and green though.

 

[exnisstech]

I forgot to add the sarcasm meter at the end bc of that!!

The sarcasm was dripping off my fingers as I typed it

It wasn't that bad but I keep forgetting how sensitive people can be. My last statement is defined below.

 

[saltcats]

ChatGPT is basically very fancy predictive text; it doesn't actually know anything.

My 50 gallon went from 5 gallons every 3-4 days in winter with heating running and drying out the air; to well over 10 days now without having to refill my 5 gal reservoir as the air is so humid here in summer.

 

[Ballyhoo]

It depends on multiple factors - some will increase evaporation, some will decrease it. It also depends on your definition of 'pretty quickly'. Clearly, water evaporates (which would be 'pure' water), but whole salt water is also lost in many tanks via splashing, skimming, etc. I don't know why you're wanting to ignore your 10 gallon sump (which is 20 percent of your water) - it should also be included.

oh, I'm not ignoring the sump I'm just trying to understand how the situation works overall. See in my particular situation I'm not sure if the ATO level sensor was placed appropriately or not. The reason is my matt roller hangs over on the ledge of the sump as intended, and in that context the valve lies above the surface of the sump water in but according to the manual the water level in the sump should be higher than the mat roller valve, or approximately at that level of matt valve. so I have this habit of continually manually adding water from the ATO tank into the sump because I wanna make sure the Matt roller has the water level the manual says it should have. and consequently, my ATO app is always indicating a full sump. Which is odd because my sump is only about how full. at this moment, since I added water yesterday, now the sump water level is well below the reef mat flow valve. But rather the ATO thinks the sump is overflowing practically I'm also gonna show a picture of where the ATO sensor level is since I know there are so many brighter minds than mine here. I realize I posted a lot of photos on my system maybe an overload for some raiders here. I'm just trying to understand things better, evaporation, and how to check and make sure my sump level is at the right level independent of how the ATO might regulate it. Thanks!

 

[KrisReef]

i

i thought more water evaporates in summer

That would be a reasonable assumption but not necessarily accurate, or helpful, or true.

My evaporation rate increases anytime of year when the local wind speed picks up, and slows when it gets still. Ambient temperatures combined with relative humidity are helpful indicators and the operation of the skimmer also impacts the rate greatly.

Slow season I go through 5 gallons every two weeks, and windy dry weather I can evaporate a 5 gallon bucket every three days.

Surface area of the tank is probably less important for my situation than the operation of my Reef Octopus 3000 skimmer. All that air/water interface heats, cools, and strips water faster than the static evaporation at the water surface.

E=MCC is much simpler to work with because there are fewer variables, according to Albert.

 

[Fred A.]

I was trying to calculate just generally what the evaporation rate is of my 42 gallon reef tank not considering it's 10 gallon sump which is in the cabinet. I use ChatGPT4 and put in the factors of room temperature 70°, humidity level 50% and water temperature of 81° and ChatGPT4 basically gave me nothing. I'm just wondering if I have 41 gallons of 81° water cubed tank how much generally should I expect evaporate in a day? one gallon.gallon . 1 litte? There's gotta be a ballpark figure at least . I understand. We also have to figure in the surface area of the water. Mine is a cube about 23 x 22". Any ideas just roughly about how much water I might be a evaporating in a 24 hour period? I know there's no way to come up with a concrete answer without doing a mathematical equation, particularly involving surface area of water and maybe surface temperature of water. what else is there? thank you.
edit, I think it's fair to say that if somebody has a reef tank that's 81°, and they live in a typical home with out significant humidity inside the house and you're in 70° room temperature that that water is gonna evaporate pretty quickly? Especially the differential between the warm water and the much cooler air. Not to mention the circulating water from the pumps and reef waves.

I read once that on average you can lose 5% per week, based on a bunch of factors. I have an RO unit under my tank that automatically tops it off ( the sump) without any work on my part. But you need a water and drain line nearby for it to work.

 

[KStatefan]

See in my particular situation I'm not sure if the ATO level sensor was placed appropriately or not.

I do not have a red sea tank but in most systems the sensor goes in the chamber with the return pump.

Pictures are always good.

 

[MnFish1]

I do not have a red sea tank but in most systems the sensor goes in the chamber with the return pump.

Pictures are always good.

The best way to do it is to measure the drop in volume in the return chamber over a couple days (with the ATO off) - IMHO - with a RedSEA - and true the ATO should go in the return chamber.

 

[hsp]

FWIW, I am often amazed by the fluctuations in evaporation. Some changes are easy to explain, e.g. my cooling fans going over the surface here in the hot Sydney summer, but other times, I cannot explain changes. As others have stated, an ATO is the solution, not necessarily a calculator.

 

[Ballyhoo]

I think for some reason, my curious mind just like an answer as to how to calculate. But I think this thread is proven They're just so many variables. Certainly humidity is gonna fluctuate, and of course, ambient temperature will fluctuate of the general evaporation, right? as well, indoor air currents, minorly fluctuate. I bet though there is an equation that would give me a rough idea or pretty good ideaof the general evaporation. it would be a perfect thing for a college algebra class to figure out.

 

[Randy Holmes-Farley]

I think for some reason, my curious mind just like an answer as to how to calculate. But I think this thread is proven They're just so many variables. Certainly humidity is gonna fluctuate, and of course, ambient temperature will fluctuate of the general evaporation, right? as well, indoor air currents, minorly fluctuate. I bet though there is an equation that would give me a rough idea or pretty good ideaof the general evaporation. it would be a perfect thing for a college algebra class to figure out.

IMO, the exact calculation is way beyond algebra. I’m sure an exact calculation involves differential equations and lots of assumptions.

Scientists more generally estimate evaporation in ways like this:

What is the formula for evaporation rate of water?

I did my own research, and according to The Engineering Toolbox,the formula for the evaporation rate of water is as follows: $g_\mathrm h = \Theta A (x_\mathrm s - x)$ $g_\mathrm h$ = amount of

chemistry.stackexchange.com

 

[charlesk]

That's exactly what I mean. But to each his own

You have way too.much time on your hands.