Tank water and bore water do not behave like town supply, and neither of them is neutral. Rainwater from a tank is typically soft and low in calcium. That sounds harmless, and in a kettle it is — but in a pool, water that is short of calcium will draw it out of a rendered or pebble interior over time. The finish pays for the top-up, slowly, and the damage is not reversible by rebalancing afterwards.
Bore water is the opposite problem and a faster one. It is often hard, and it frequently carries dissolved iron or manganese. Those stay invisible in the ground and then oxidise the moment they meet chlorinated pool water, which is why a pool can go brown or black within a day or two of a large bore top-up. Pre-treating during the fill is straightforward. Removing the stain afterwards is not.
The exposure question runs alongside it. With so few buildings across the western part of the locality to break the wind, dust, grass clippings and paddock debris get carried across open yards and into the water. Grass and fine dust load a filter differently to leaf litter — they pack tighter and lift pressure faster — so filter pressure is checked on the schedule the pool actually needs rather than on a standard interval.
And then there is simple visibility. A pool at the back of a large block is out of sight, and out-of-sight pools are the ones that quietly go green. Consistent, scheduled visits matter more here than in a suburb where the owner walks past the pool ten times a day. On the eastern side the same principle applies for a different reason: 41.0% of occupied dwellings in Meridan Plains are rented, the highest share of the six suburbs in this pack, and a rented pool is one nobody has quite taken ownership of.
