Leak or evaporation (with a twist)

[Jaxbchjim]

Hi,

New IG pool in NE FL completed in April. Pepple Tec "marcite" with Rico Rock coping and waterfall. Losing 3.5" water per week, far more than our previous pool which was just a few miles away. Multiple bucket tests show 1/4" loss from bucket, 1/2" from pool per day, even without water features running. So a leak, right? Pool contractor did dye test and didn't find anything but sealed returns, drains, and light receptacles. No change. Leak detection specialist came out, sealed spot between Rico Rock coping and marcite. Negligible change in bucket test. Leak detection specialist came back out and his equipment supposedly shows only normal water loss equating to 1/4" per day but I'm still losing 1/2".

Here' where it gets interesting. When I challenged our contractor on why my bucket test shows twice the loss from the pool than the bucket, his theory is that the Rico Rock coping may be the culprit due to either seepage through the cementious "rock" or greater evaporation along the coping due to how the water wicks up the Rico Rock moreso than tile coping. So we drained the water below the Rico Rock coping and ran water through drain with skimmer off. Loss for pool and bucket were about the same (strangely the bucket seemed to lose a bit more than the pool).

The Rico Rock wicking thing seems like a stretch to me however the water does wick up the Rico Rock coping about 1/2" above the water line. Could that cause an extra 1/4" per day? I suspect there may be a gap somewhere between the Rico Rock and the Pepple tec "marcite" but would the shell "catch" the water before it could go too far? This is a free-form pool, ~12K gallons with two tanning ledges.

Apologies for the novel but wanted to provide the full story. Any ideas, particularly from anyone with experience with Rico Rock coping?

 

[tim5055]

Welcome to TFP!!

It would seem your second bucket test with the water-level below the rock has proven the "wicking" and I can believe that it would evaporate quicker at that point. The wicking 1/2" above the water line is obviously creating additional surface area to evaporate.

 

[Jaxbchjim]

Thanks Tim. Do you think that the wicking effect could contribute to 1/4" additional evaporation per day? Seems like a lot, basically equivalent to what is evaporating from the pool and water features. My only other thought: when the water was drained below the coping I obviously had to turn off the skimmer. Perhaps there is a leak in the skimmer or its plumbing. But being suction side would I see bubbles in the retunrs if that was the case?

I would be especially interested if any others that have Rico Rock coping could weigh in on whether they have similar results re high evaporation rate.

 

[cowboycasey]

lets break this down from my limited level (I suck at math and conversions, so someone feel free to jump in and correct me )

you don't have how big your pool is but lets say you have 80 feet of rico rock tile line

80ft x .5 inch's = 480 sq inches of constant evaporation

from this website, Cubic Inches to US Gallons (Liquid) conversion 480in³= 2US gal lqd

what I don't know is the time that those 2 gallons of suspended liquid are evaporating.

lets say those 2 gallons are evaporating every 10 minutes

2x6 =12 gallons an hour x 14 hours a day = 168 gallons a day

what if its every minute 2x60=120x14=1680 gallons a day

from what you are seeing I think its somewhere between those 2

ok everyone, am I way off

 

[Jaxbchjim]

80ft x .5 inch's = 480 sq inches of constant evaporation

from this website, Cubic Inches to US Gallons (Liquid) conversion 480in³= 2US gal lqd

what I don't know is the time that those 2 gallons of suspended liquid are evaporating.

Thanks Casey however the trouble with that logic is that you mixed square inches with cubic inches. 480 square inches wouldn't come anywhere close to 480 cubic inches since the layer of wicked water is super-thin (perhaps a few molecules??). If the wicked water was 1/50" thick that would equate to roughly 10 cubic inches. Granted the surface tension of that water is lower than the pool water, but I'm struggling to imagine how that little amount of water could generate as much evaporation as the entire surface area of the pool.

 

[JoyfulNoise]

I'm going to go with Occam's Razor on this one - double check your skimmer for leaks! You dropped the water level below the skimmer and the leak basically stopped. You need to rule out the skimmer as they can be know sources of leaks if they are not installed and sealed properly.


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[JoyfulNoise]

Also, this is off topic a bit, but if your stone tiling and coping is that porous, you might want to consider sealing it. That much water permeation is bound to result in efflorescence and cause major calcium nodules and stains. Is that stone meant to be used like that at the water line? Typically water infiltration into soft, porous stone is not a good thing.


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