Preparing Your Pool for Cooler Months
Some pool owners live in climates where a pool can be left open throughout the year. Below are tips for what to do when the swimming season ends and the pool becomes a water feature.
Water Chemistry During Winter Months
As the weather cools off, you will notice that caring for your pool involves less effort than during the warm Summer months. You can continue to care for your pool the same way during these cooler months, but realize that the amount of chlorine required to maintain the water will slow dramatically. This is due to the sun angle being much lower and burning off less chlorine than during the hot summer months.
If you utilize a Salt Water Generator during the Summer, you will want to switch to Liquid Chlorine as many SWGs stop generating when the pool water gets between 50°F and 60°F. During this time, you should switch to the Liquid Chlorine targets on the FC/CYA Chart.
Lastly, pool owners who have a plaster pool will want to watch their Calcium Saturation Index as CSI decreases as the water temperature gets colder. Raise the pool pH to keep CSI above -0.6 to avoid damaging a plaster pool's surface through etching.
Equipment Over the Winter
During the Winter, users can minimize their pump run time and only run it to keep their chemicals mixed. If trees drop leaves into your pool, you may want to consider some skimmer leaf guard. This will help prevent your skimmer from clogging and starving your water pump.
Some manufacturers of gas heaters warn that cycling the heaters on and off when the water is less than 70°F can cause damage. Because of this, you should be mindful that using your heater to keep pool water above freezing can cause damage. You can read more about this in Heater Condensation. If you opt to run your gas heater with water below 70°F, it should be done in one cycle to get your water above 70°F. Then keep it above 70°F using the heater if desired.
Contingency Planning for Freezing Weather
As the warm weather gives way to cooler temperatures, it's essential to be prepared for the possibility of freezing weather, especially if you live in an area that doesn't typically experience freezing temperatures. Freezing weather can be hazardous if short-lived and unexpected, as it can catch people off guard and leave them unprepared.
Being prepared for freezing weather is especially important when you have a swimming pool. When the temperature drops below freezing, the water in your pool can turn to ice, damaging the pool's pump and pipes. To avoid this, it's a good idea to take a few minutes to learn how to shut down your pool and drain the system while the weather is still warm. This will help you protect your pool and avoid costly repairs in a freeze.
Here are some tips for preparing your pool for freezing weather:
Keep the water moving
Moving water is difficult to freeze, so it's essential to circulate the water in your pool as much as possible. If your system has freeze protection, make sure it is operating correctly. If unsure, it's better to turn it off and manually set the system to run 24/7 until the freezing temperatures subside.
Figure out a valve setting that makes at least a bit of water pass through each pipe and piece of equipment. Or else blow them out so there's nothing to freeze. You may have deck jets, spa suction, spa bubbler, heater, or a cleaner circuit that needs attention. Putting diverters in a halfway position can ensure water flows through the equipment.
Have a backup plan for power outages
Power outages can be a significant problem when it comes to freezing weather. To prepare for this possibility, consider the following:
- Know how to drain your equipment quickly if the power does not return. Look for drain plugs on your pump pot, filter, and heater (if applicable).
- Wrap exposed plumbing and equipment with insulation materials to protect them from the freeze.
- Place a decent-weight painter's tarp (fabric or polymer) or heavy blanket over the equipment pad. Some might even place one or two contractor/painter lamps with 100W incandescent bulbs under the tarp for warmth.
- If you have accessories you can't keep running (e.g., waterfalls, spill-overs, etc.), consider closing them in advance. If you can access the outlet area of the feature, try vacuuming out some water close to the ground's surface or plumbing exit and adding some RV antifreeze to the plumbing at that exit area for insurance.
- Watch for standing water. This can be a problem for waterfalls as the water may slip into cracks and grout areas and then later expand and cause damage. Remove standing water and/or cover the area with a tarp if possible.
- If the power does not return for a long time, have a couple of pieces of cut-up pool noodles or a plastic jug (half full) to place in the skimmer(s). Also, consider covering the skimmer lid to prevent it from freezing and getting stuck in place.
- Autofills: Remember that any exposed autofill line will not have water actively moving through it. Water only moves when it's filling the pool. If possible, shut off the autofill line and purge some water from it to prevent expansion in the line. At the very least, wrap any exposed autofill lines well.
- Heaters: It's best to allow water to run through them, but do not activate the heat mode. Only allow water to flow continuously. As with other equipment, know where your drain plugs are in case power is lost for a significant amount of time.
- Inspect all areas at the equipment pad for leaks. Tiny leaks will be the first to freeze and could harm equipment. If possible, try to resolve them or take extra precautions to protect the area from freezing.
Following these tips and being prepared can help protect your pool from freezing during unprecedented cold weather.
The Physics of Freezing and Freeze Protection
To understand when to worry about the pool or equipment freezing, read The Physics of Freezing and Freeze Protection.
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