Closing, covering and opening again

Two short jobs decide whether you own a pool next year

A seasonal pool spends more of the year not being swum in than being swum in, and almost all of the expensive mistakes happen during that part. Closing badly is the single costliest thing a first-year owner does — not because closing is difficult, but because the consequences arrive six months later when the liner comes out of the shed cracked, or does not come out at all because it froze in place.

The two jobs are closing in autumn and opening in spring, and each is an afternoon. What follows is the shape of both; the step-by-step versions are at winterizing an above-ground pool and opening in spring.

Closing: cold water first, then chemistry, then the cover

The sequence matters and most of the errors are sequence errors. Wait until the water is genuinely cold — closing a warm pool leaves it biologically active under the cover all winter, which is how people find a swamp in April. Balance the chemistry before you close rather than after, because unbalanced water sitting still for months is what stains and corrodes.

Then drain to the manufacturer’s stated level, disconnect and fully drain the pump, filter and every hose, and store them somewhere that does not freeze. Water left in a pump housing expands when it freezes and cracks the housing; that is the most common winter loss and it is entirely preventable in ten minutes. Finally cover it, and if you are in a freezing climate, float something compressible in the middle so expanding ice pushes against that rather than against the wall.

For a soft-side or small frame pool the calculus is different: empty it, dry it thoroughly, fold it and store it indoors. A pool left up all winter in a cold climate is a pool you are gambling with.

Covers do two different jobs — buy for the right one

The word “cover” hides two unrelated products.

A solar cover is a summer item. It is a sheet of bubble material that floats on the surface, limits evaporation and returns some heat to the water overnight. It is probably the highest-return accessory in this entire site, because evaporation is simultaneously your water bill, your chemical bill and your heat loss, and a cover reduces all three at once. It is not a safety device and it will not hold weight.

A winter cover is a structural item. Its job is to keep debris and sunlight out for five months while carrying rain, snow and ice. That means straps or a cable, genuine tear resistance, and enough slack to sit on the water rather than stretch across it. Buying a summer cover for a winter job is a common and expensive substitution.

Kits, and what they save you

A closing kit bundles the winterizing chemicals into one box at a slight premium over buying them separately. For a first close it is worth it, mostly because the failure mode of buying item-by-item is discovering on the day that you are missing one thing. By the second year you will know what your water actually needs and can buy it directly.

Opening is easier than the internet suggests

Spring is the reverse in a shorter afternoon: get the debris off the cover before you move it, top the water back up, reconnect and prime everything, run the filter continuously for a day or two, then shock and balance once the water is circulating. Nearly every green opening is a pool that was uncovered too early or reconnected too late, not a pool that needed more chemicals.

Two links worth having open while you do it: the cloudy water decision tree, because opening water is almost always cloudy for a few days and that is fine, and the annual cost guide, because closing and opening are line items in a pool year that most budgets leave out entirely.