STRUCTURE AND SURFACE
Is the level dropping from evaporation, or a leak?
One bucket and 24 hours will tell you: if the pool drops noticeably more than the bucket does, it is a leak and not evaporation.
In this climate an uncovered pool loses roughly 3–7 mm a day, or 2–5 cm a week. April, with strong sun and wind, runs higher, and a pool that uses a counter-current unit or a heat pump loses more again. So a few centimetres a week is still normal.
The bucket test
Top the pool up to its normal level — the middle of the skimmer mouth — then switch the pump off, and any auto-fill with it.
Stand a plastic bucket on a pool step so its base is submerged and it sits still. If it floats, weight it with a stone.
Fill the bucket until the water inside it is exactly level with the pool, then mark two lines: one inside the bucket for the bucket's level, one outside for the pool's.
Leave it 24 hours. No swimming, no pump, no topping up — and not on a rainy day.
Read both marks. If the bucket and the pool dropped the same, it is pure evaporation and there is nothing to fix.
If the pool dropped 3 mm or more further than the bucket, you have a leak.
Once a leak is confirmed, run the whole test again for another 24 hours — this time with the pump running throughout.
Compare the two runs. Losing water noticeably faster with the pump on points at the return pipework.
Losing it at the same rate either way points at the pool shell itself.
Note which of the two it was, and tell us when you call.
Where to look before you call
Ground around the pool that stays soggy, or a patch of grass greener than the rest with nothing watering it.
Cracks or crumbling grout around the skimmer faceplate — the most common leak point on any pool.
A constant stream of bubbles from a return, which means air is getting into the suction side — often alongside a leak in the pipe.
A level that falls and then stops at a particular height. That height is where the leak is — note it and tell us.
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