Filling the pool for the first time, step by step

How much water you need

The volume is length × width × average water depth. A 4 × 8 m pool with a water depth of around 1.40 m needs about 45 m³, which is about 45 tonnes of water. Keep this number handy: you will need it for every chemical dose from now on.

With a garden hose, a fill like this often takes more than 24 hours, depending on mains pressure. That is why it is scheduled together with the installation crew, so the pool is not left half full.

Where the water comes from

If you fill from a borehole

Borehole water can look crystal clear and still contain iron, manganese or copper. As soon as chlorine goes in, the metals oxidize, the water takes on a brownish or greenish tint and it can leave stains on the liner. A laboratory analysis before filling shows whether you need a metal sequestrant or pre-filtration. With boreholes near the sea, also check the salinity, and hard water needs scale prevention (see water hardness).

How the liner settles

During installation, the air between the liner and the walls is removed by suction so the membrane takes on the exact shape of the pool. Filling starts while the suction is still running. The small folds in the floor are smoothed out in the first few centimetres of water, because later the weight of the water "locks" them in place.

• Do not step into the pool with shoes on, and do not let sharp objects touch the liner.
• Do not stop filling halfway for days; the liner must stretch evenly.
• The openings for the skimmer, return inlets and lighting are cut when the water reaches just below them, so the gaskets and face plates go on with the liner taut.
• Filling continues to about the middle of the skimmer mouth, or to the level set by the overflow.

If you see folds after filling, do not pull at them yourself; let whoever installed the liner know. Causes and prevention are covered in wrinkles in the liner.

The first chemical balancing

With the pool full, backwash and rinse the filter to clear the dust from the new filter media, and let the pump run continuously for the first 24 hours. Then follow this order:

1. Test all the parameters; testing the right way matters from day one.
2. If the water is from a borehole with metals, add a metal sequestrant first.
3. Correct the total alkalinity.
4. Bring the pH to 7.2–7.6.
5. Do the initial chlorination so free chlorine settles at 1–3 mg/l.

Add each product separately, with the pump running, and test again before the next one. In the first few weeks, test more often, because new water often needs a few corrections before it is balanced.

Never put chlorine granules directly onto a new liner. Dissolve them in a bucket of water and pour the solution near the return inlets. And remember that a liner pool, once filled, is never completely emptied.

Questions

See also