· by Michael Blair, Nashville's Pool & Spa
In Middle Tennessee the leaves come down from October into November, and a pool surrounded by oaks, maples and sweetgums can collect more in a week than it did all summer. Leaves that sink and sit on the floor release tannins, the same compounds that turn tea brown, and leave stains in the shape of the leaf on plaster and light finishes. They also add a heavy organic load that uses up chlorine, and they pack into skimmer and pump baskets until the pump is starved of water. None of it is hard to manage, but it takes more attention than the pool needed in August.
What leaves do to the water
A leaf is organic material, and chlorine spends itself breaking organic material down. A pool that held a steady reading all summer can drop to nothing in a day or two when leaves are piling in, and low chlorine plus cooling water is an easy setup for algae. Decaying leaves also release phosphates, which algae feed on.
Test more often during the drop, not less. Leaves skimmed off the surface before they sink cost almost nothing; leaves left to steep on the floor cost chlorine, time and sometimes a stain. A pool that turns faintly yellow or tea-tinted overall, rather than in spots, is showing the same tannins dissolved through the whole body of water, and it clears with filtration and a good shock once the leaves are out.
A brown stain: organic or metal
Leaf stains are brown or tea-colored, often with the recognizable outline of the leaf, and they appear where leaves sat: the deep end, the steps, corners out of the circulation. Metal stains from iron or copper look different, more rust, green, blue or black, often spread across a wall or near the return jets, and they are not shaped like anything.
The simple test is to hold a chlorine tablet or a small amount of granular chlorine against the stain for a few seconds, in a sock or a sealed container on a pole. An organic stain lightens. A metal stain does not, and may respond instead to an ascorbic acid tablet held the same way. Organic stains usually clear with shock and brushing over a few days. Metal stains need a different treatment and a look at where the metal is coming from.
Skimmers, pumps and the leaf canister
A skimmer basket full of wet leaves blocks flow to the pump. The pump keeps running, pulls air, loses prime and can run dry, which overheats the seal and can crack the pump housing or melt fittings. During peak leaf drop, skimmer baskets may need emptying every day, and the pump strainer basket needs checking as often.
A leaf canister, an inline trap on the vacuum hose, catches leaves before they ever reach the pump when the floor is vacuumed. Trimming limbs that hang directly over the water takes the load down for every year after.
- Skim the surface before leaves sink
- Empty skimmer baskets daily during the drop
- Check the pump basket and listen for the pump pulling air
- Use a leaf canister on the vacuum line
- Test chlorine more often, and shock after heavy days
Close early, or keep it running
Some owners close before the leaves fall so the cover takes the whole drop. A mesh safety cover lets water and fine debris through but holds the leaves on top, where they are raked or blown off. A solid cover keeps everything out but collects rainwater and leaves in a heavy, sagging layer that needs a cover pump. A leaf net stretched over either cover makes the clean-up a matter of lifting the net and carrying it off.
Closing before the water cools can mean closing warm water that still grows algae under the cover, so the chemistry at closing matters more when you close early. Keeping the pool open through the drop and closing once the leaves are down is the other route, with more skimming work. Whichever you choose, do not close with leaves on the floor. They sit under the cover all winter and leave the stains waiting for you in spring.