When to Do a Full Pool Water Replacement

Most Sanur villa pools do not need a complete water swap every year. But persistent algae stains, salt or mineral buildup, and a long wet-season stretch can make a full drain unavoidable. Here is how to tell when it is truly time, what can go wrong during the process, and what happens once you start emptying the basin.

When You Actually Need a Full Replacement

A few signs mean topping up and shocking will no longer save the water. The most common one is a greenish or brownish tint that survives two or three rounds of algaecide and super-chlorination. If the colour sits in the tile grout or on the step edges, it has bonded and only a fresh fill will clear it.

Another trigger is scale. Sanur's sea air pushes calcium and magnesium into the water over months. When you see white crusty rings around the skimmer or a chalky film on the deep end, the chemistry has shifted past easy correction.

After a heavy rainy season, many old villas near the coast find their pool water cloudy with silt and organic matter from the surrounding garden. If the filter has been running non-stop for days without clearing things up, a full swap is usually the faster fix.

• Colour or stains that survive repeated chemical treatment
• Visible calcium or salt scale on tiles and fittings
• pH and alkalinity that keep drifting despite dosing
• Post-rain contamination that the filter cannot clear

Risks of Draining a Pool in Sanur

Old villa pools here were often built with thin gunite shells and minimal reinforcement. A sudden, fast drain can put uneven pressure on those walls. We always lower the level slowly so the structure adjusts gradually.

The bigger risk is electrical. Once the water drops below the pump intake, the motor runs dry and overheats. Pool lights and underwater sockets are also exposed. If you smell burning plastic or see any sparking near the equipment box, stop immediately and call a licensed electrician before touching anything else.

Chemical safety matters too. Mixing leftover chlorine tablets with acid-based tile cleaners releases toxic gas. Never combine products in an empty basin. If fumes appear, ventilate the area and get fresh air; do not re-enter until the space is fully aired out.

How We Handle the Drain and Refill

First we isolate the pump circuit at the breaker panel and confirm the motor is off. Then we open the main drain valve and let gravity pull the water toward the septic or municipal line. On most Sanur villas this takes two to four hours depending on volume and PDAM back-pressure.

While the pool empties we keep an eye on the skimmer basket, return jets, and the deep-end floor for debris that was hidden under the surface. Any loose tiles or cracked grout lines get noted now, because they are much easier to flag while the basin is dry.

For refilling we use whichever source is available: PDAM mains if pressure holds steady, or the villa's well and rooftop tank if the street supply is intermittent. Filling slowly—roughly one metre per hour—protects the shell and lets us check for leaks before the water level rises again.

Cleaning the Basin Before Restarting

With the pool empty we scrub every tile face with a stiff brush and a mild descaler. This lifts the mineral film that regular brushing from above never reaches. Grout lines get a separate pass; in older pools the grout can be soft and crumbly, so we go gently to avoid widening gaps.

The skimmer throat, return nozzles, and any underwater lights get cleared of scale and algae residue. We also inspect the drain cover and the anti-vortex fitting at the bottom for cracks or corrosion from years of salt air.

If there are stubborn rust stains from iron in well water, we treat those spots with a dedicated acid wash before filling. Leaving them means they will bleed colour back into the fresh water within a week.

Filling Back Up and Balancing the Water

Once the basin is clean and dry, we start the fill. The first hour is slow so we can watch for any seepage around the shell joints or the light housings. If everything holds, we let it run at a steady pace until the level sits just below the top of the skimmer opening.

With the pool full we circulate the water through the filter for at least two hours before testing. Then we check pH (target 7.2–7.6), total alkalinity, and free chlorine. Because Sanur's tap and well water vary by neighbourhood, the starting numbers differ every time, so we dose to what the test strips actually show rather than guessing.

We recommend waiting 24 hours after balancing before anyone swims. That gives the chlorine time to stabilise and lets you confirm the water looks clear and feels neutral on the skin.

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