Water evap at 80 degrees

cfclay

Well-known member
Apr 24, 2010
281
Lexington,Ky
Greetings from Lexington Kentucky. My youngest twin girls have now turned 18, and between them and my adult son with autism- this 30’ I built four years ago. Sure didn’t get much use this summer. at least I did develop a Zen with very little maintenance required in the way of chemicals all summer.

I’m wondering if I have a leak, I see no evidence of it outside the pool. No rain in the last seven days, and I was at this same point six days ago and added maybe 3/4 to 1” and now I’m back to sucking a little air and need to raise the water level.

80° temps for the last six days, how much water evaporates in that kind of temperature. Full sun for most of the day.

Thanks in advance.
 

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Pool temp, daytime temp, nighttime temp and humidity all play into the evaporation rate.
Sometimes times, the humidity can change drastically throughout a 24 hours period as well.
 
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80° temps for the last six days, how much water evaporates in that kind of temperature. Full sun for most of the day.
Your 'seasonal weather' just showed up. A couple weeks back my evaporation spiked and it's due to the days staying where they were but the nights hovering at low 60s high 50s.

A couple weeks later my daytime highs dropped and with less swing, the evaporation let up.

Keep an eye on it and adjust as necessary but you're likely fine.
 
If you are concerned, do the bucket test.

Fill a clean 5 gal bucket with your pool water, up to 2-3 inches from the top, and mark the water level with a sharpie.

Sit the bucket on your pool steps, so that it is mostly submerged and mark the pool water level on the outside with a sharpie.

Let it set 24 hours or so. Compare the loss IN the bucket to the loss OUTSIDE the bucket. If it is the same, then no leak.

If you do not have pool steps, then you can sit the bucket near the pool and put a mark with with tape on your skimmer.

The reason for sitting it on the steps is twofold. It lets you mark the pool water level with a sharpie, and it also ensures the pool water and bucket water stay the same temp.
 
Cold nights with warm pool water increase evaporation.
That might be true, but there seems to be conflicting opinions about this.

The rate at which water evaporates from any surface, whether from a lake's surface or through the stomata on a plant's leaf, is influenced by climatic and weather conditions, which include the solar radiation, temperature, relative humidity and wind (and other meteorological factors). Evaporation rates are higher at higher temperatures because as temperature increases, the amount of energy necessary for evaporation decreases.

In sunny, warm weather the loss of water by evaporation is greater than in cloudy and cool weather.

Humidity, or water vapor content of the air, also has an effect on evaporation. The lower the relative humidity, the drier the air, and the higher the evaporation rate. The more humid the air, the closer the air is to saturation, and less evaporation can occur.

Also, warm air can "hold" a higher concentration of water vapor, so you can think of there being more room for more water vapor to be stored in warmer air than in colder air.

Wind moving over a water or land surface can also carry away water vapor, essentially drying the air, which leads to increased evaporation rates. So, sunny, hot, dry, windy conditions produce higher evaporation rates.


The Anderson Estimator does not even use the air temperature.

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Heat a pot of water on the stove and the warmer the water gets the quicker it will evaporate.
 

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Do the bucket test to confirm/deny evaporation - super easy.
 
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I usually do the soft close (deploy the cover) until the water temp drops to low 60’s then drain/winterize.
I have a swcg so even with minimal run time my fc usually climbs with the cover on so raising to slam doesn’t require quite as much liquid chlorine. When the time comes I peel back the cover a little, mix my liquid chlorine in & throw the robot in for a swim before doing the draining/winterizing.
I like this method because its not an all day event. Little bites spread out over some days. My kiddos help with the cover then I can do the rest at my leisure.
 
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I like this method because its not an all day event. Little bites spread out over some days.
This is exactly how I inadvertently soft open most years. Lol. I'm chomping at the bits each spring before it's time. So I do it in stages to keep busy and lessen the load as time permits. I get the equipment set up and turned on. Then I casually bring out the furniture/ floats / etc etc and eventually when it's warmed up, pop the cover.

My soft closes started the same way, just looking to spread it out when I had little kids who needed time/attention and 4 rides to class birthday parties each weekend.
 
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