pool leak?

[Shakushinnen]

Hi,

I have a 100,000 litre above ground pool, installed sometime in the 80's. It's all concrete, with a vinyl liner. This year, for some reason, it seems to be using more water than usual, and I'm wondering if I have leak somewhere. There's no visible sign of a leak, but of course all the plumbing is underground (ABS). Does anyone know how I might check for a leak?
Thanks,
....... john

[Anonymous [GDPR] European in the UK]

Hi John, the very first thing as there isn't evidence of a leak is to do an evaporation test. fill a bucket, mark the water level and leave it in the pool on the steps maybe. the water in the bucket should evaporate at the same rate as the pool, any more and you have a leak. If that the original liner then you could be due a replacement.
Good luck and let us know.

[Shakushinnen]

Hi Teapot,
I'm doing the evaporation test now. Yes, it is the original liner.
Thanks for your help.
........ john

[Shakushinnen]

Hi Teapot,

Well, I finally have the results of the 'bucket' test. In the pool water I lost about 2/3" of water over two days, which works out to 38cu ft. (if my calculations are correct. This is 284 US gallons or 236 imperial gallons.) In the bucket I lost 2/5" of water over the same period, 2 days. This is 178 US gallons. I estimate the surface area of the pool to be about 700 square feet. Does this sound like normally evaporation rate to you?

Thanks,

...... john