I have a strange one here, hoping you can help. Customer has pool with separate inground spa, with half of the water below grade and half of the water above grade. There is a flagstone cap without coping on the top wall of the spa, which looks good and is comfortable seating.
Equipment is below water level on hillside. Pool has auto-fill but spa does not. I service the account weekly, and need to drain water out of the spa every week, because the water level rises slowly up to a point where it can seep through the grout under the flagstone cap, then leak down the outside wall and form a puddle on the pool deck.
Sometimes I have found sticks from the nearby bougainvillea causing the weir to jam closed on the spa side of the stopper in the top of the skimmer. Other times even though there is no stick, the weir has somehow flapped to the spa side of the skimmer opening, so water cannot easily get past it into the skimmer.
The pool owner tells me it takes about a day for the spa water level to rise from "mid-waterline tile" to the overflow point.
2 weeks ago, we put a 1" pvc pipe into the ceiling of the skimmer opening space above the weir, preventing the weir from backflapping and getting stuck. Now it takes about 4 days for the water level to increase to the overflow point.
The system is closed, with a pump, filter and heat pump, and a separate booster pump for the jets. The pool water and the spa water do not mix. We have not had measurable rain to blame for the water rising. How could this be happening?
Any ideas? Thanks