1. Balance the water chemistry.
About a week prior to closing the pool, adjust your water balance within the ranges below:
- pH: 7.2-7.4
- Alkalinity: 80-120 ppm
- Calcium Hardness: 180-220 ppm
Several days before closing, shock the pool with a chlorine shock or non-chlorine shock, using at least 2 lbs per 10,000 gallons (follow package directions). Allow the chlorine level to return to 1.0-3.0 ppm before adding any winter algaecide or your pool cover. Very high chlorine tends to break down both algaecides and pool covers. Never add chlorine shock and algaecide at the same time and not right before covering it. At the very least, shock the night before you plan to close the pool, and run the filter all night long.
2. Remove skimmer baskets, wall fittings, cleaners, solar blankets and ladders from the pool.
Put these in a safe location during the winter. Don’t coil pool cleaner hoses tightly, and be sure the cleaner and hose are completely drained.
3. Clean the pool.
Skim, vacuum and brush the swimming pool. Leaf rakes or “bag type” skim nets work best, and are useful for scooping large amounts of leaves/debris from pool floor. If the pool is especially silty or has lots of algae, vacuum the pool to waste. This means to bypass the filter and vacuum dirt from floors/walls out the waste line. This prevents constant clogging and cleaning of the filter. Place the multiport filter valve on drain to waste position (usually at 2 p.m. position if viewed as a clock face). If you have a push-pull filter valve or a cartridge type filter, there is no easy way to vacuum to waste, unless you cut the pipe coming out of the pump and then reconnect it afterwards with a union or valve. Brush the pool thoroughly after vacuuming. The pool should be as clean and clear as possible before covering, so give it one more skimming right before putting on the cover. If possible, give your pool some extra filtering before closing, and run it 24 hours a day for a few days.
4. Lower the water level in the pool.
Using the filter pump or a submersible pump, lower the water level 12″-18″ below the skimmer for mesh covers, or 3″-6″ below the skimmer for solid floating covers. If you are using a skimmer cover for your above ground or inground pool, the water level will not need to be lowered. For pools with a separate main drain, close off the skimmers and drain to waste (DE and sand filters) out the waste line. For cartridge filters or systems with no main drain, use a submersible pump or self-priming pump on the deck to lower the water level. If your method of lowering the water will take several days, cover the pool to keep it clean.
5. Drain all pool equipment.
Most every pump, filter, heater and chlorinator will have drain plugs or caps to allow water to drain out. All water must be drained or blown out of your pool equipment, or it will freeze and crack. After draining, DE filter grids or cartridge filters should be removed and cleaned thoroughly. If the filter and pump is small enough to remove and store indoors, this may be desirable. If not, a small amount of air from a shop vacuum, compressor or blower can be used to blow out any water that may still be in the equipment. Keep the drain plugs removed during winter in case any pipes become un-winterized. You can store the drain plugs in the pump basket for safe keeping.
6. Lubricate the o-rings on equipment.
Fall pool closing is a good time to lubricate the pump lid o-ring with Magic Lube. If you have a push-pull valve (also known as a slide valve) on the filter, lubricate the plunger o-rings as well. If you have a gas heater with cast iron headers and brass plugs, lubricate these threads or leave the plugs in after draining to prevent rusting. Filter belly band o-rings or union connection o-rings can also be lubed for better sealing and weather/chemical resistance.
7. Winterize plumbing to and from the pool.
If you have an inground pool, you should clear all water from the plumbing lines. Use a blower to push air from the skimmer, through the equipment, and back to the pool. Next, plug the lines in the pool using expansion plugs. If you don’t blow the lines, add swimming pool antifreeze into the line per package instructions. Above ground pools usually just need to disconnect the hoses to and from the pump and filter, and then plug the wall outlets. But if hard PVC pipe is used, either blow out and plug the lines, or use pool antifreeze to prevent freeze damage.
8. Add winterizing algaecide and floaters.
Remember not to add algaecide and chlorine shock at the same time (non-chlorine shock is OK). Walk your liquid chemicals around the pool for best distribution. Vinyl pools should not use chlorine pool floaters to avoid color bleaching or damage to the vinyl liner, but they can use non-chlorine winter floaters instead. For plaster pools, use a chlorine floater large enough to hold 8 tablets (for pools up to 30,000 gallons). To reduce the chance of a floater tipping over or coming to rest on a step or swimout, tie it off in the center of the deep end using a long string or twine. Algaecide and chemical floaters are the typical sanitizers used to winterize pools. Enzymes can also be used to reduce sanitizer demand, and they’re popular for pools with mesh safety covers. If you have a warm, early spring, or you wish to prevent a green pool opening, plan to add more algaecide and/or refill the floaters in mid-spring.
9. Cover the pool.
A tight fit of your pool cover is essential. Your cover should not have holes or gaps where leaves and debris may enter the pool. A safety cover provides the highest protection and safety. Solid pool covers will not protect people or animals from falling into the water, and they also require a cover pump or siphon to remove rain water and snow melt. Water bags or Aqua Bloks are used to secure an inground solid pool cover. Above ground pool covers use a cable and winch device to secure the cover around the pool. Air pillows are used in above ground pools to absorb the expansion of ice inside the pool. In areas of high wind, an above ground pool owner will find wall bags or cover seal to be useful products. A leaf net is very useful if you have a lot of trees surrounding your pool.