Why Pool Covers Don’t Last

Sunday, September 25th, 1994

People lose hundreds of dollars by making common pool closing mistakes

It’s a tough ethical dilemma. Every fall, we try to tell people how to close and cover a pool properly and economically. Many consumers act like we’re trying to put something over on them, yet each piece of advice here ultimately takes money out of our pockets, and puts it into yours. Especially when it’s busy, we don’t have time to argue. Here are a few of the most common mistakes made.

Wrong Cover Size
Pool covers are commonly marked with the largest possible pool size that the cover will fit. That isn’t necessarily what’s best for your particular pool. A tight cover will eventually stretch and open small holes that let dust and algae into the pool. Generally, a cover that lasts less than ten years was probably too tight for the pool. This is not considered a problem in the industry. If you purchase a new cover every five years instead of every ten years, we all sell twice as many covers!

You should be able to put on a pool cover so that it is completely loose even after an entire winter of rain and snow. That means that you need to estimate how far down the water level will be in spring, and know the distance around the top rail or coping. For most pools, the three-foot overlap on above ground pools, or the five foot on inground pools isn’t enough.

What do you do?

  1. Take your measurements and shop for the correct cover size, not pool size.
  2. Use a winter plate and plugs (see page 4 for more information), so that the water level is higher, and you don’t need such a large cover.
  3. Pump or siphon off the cover as often as possible, to reduce water loss due to displacement.
  4. Learn how to cover the pool properly. Ask us, or read the directions. If you are using too many ice pillows, or plastic jugs, or the cover looks like a tent, you’re doing something wrong.

Draining Too Much
Draining the pool is bad for the pool walls, the liner, the plaster and the cover. It throws away perfectly good water that forces you to re-balance in spring. All this to protect a $20 skimmer body?

Many inground pools are drained below the pipes so that the lines can be drained or blown out. Pool service companies use a compressor that’s powerful enough to blow out against the water pressure, leaving the water level higher. You can rent such a compressor from a rental company (like Taylor Rental) or from us.

Many above ground pools are drained below the return, so the pool can drain out the return as it rains and snows. However, if you plug the skimmer and return properly with a stainless steel winter plate and a flat return plug, you can leave the water in place. Now, the pool water has to displace 6-8 inches upward before you lose a drop. In spring, the water should be right where you left it. If you don’t have to add more water, you shouldn’t have to add more Baquacil or balancing chemicals, either. That saves you about $20 to $100 depending on pool size!

Since skimmers and returns are not standardized, you need to know the brand or size before you purchase the plug and plate. Above ground pools are easy. Because of the large number of inground equipment sizes, they are more difficult.

High Chlorine Levels
Pools need to be shocked for closing, but chlorine shocks ruin pool covers and solar covers. If you use a chlorine shock, give the pool 24 to 48 hours for the shock to wear off before closing. Non-chlorine shocks for chlorine or bromine pools (potassium monopersulfate) won’t hurt your cover, so they are often used when shocking and closing the same day. However, they are not sanitizers, and they will not kill any algae or bacteria in the pool. Baquacil and Softswim shocks are not a problem—they don’t hurt the cover, and they will kill what’s in the pool.

Another potential danger is from a winter kit that uses chemical cartridges. If the cartridge builds up a high level of chlorine or other harsh chemicals in one spot due to the lack of circulation, the cover can deteriorate. If the ice breaks the cartridge open and the tablets land on the liner, the liner can be ruined. We replace several liners every year because of this.

Mesh Covers
If you hire someone to open your pool, it probably won’t matter. Otherwise, why would you want a cover that doesn’t keep the pool clean? Water, dust, dirt, algae, bacteria, fungi, and bioslimes all go right through the mesh. Leaves, branches, snow, and ice stay on top. Since the ice can freeze into the fabric, mesh covers usually don’t last as long as solid. All of the sizing problems described above are still involved with mesh covers, because they are still frozen solid for two or three months each winter.

Early Closing
Lots of people want to close their pool Labor Day weekend. However, if the water is still warm, you have a good chance of developing algae before December. There’s only so much that a $15.00 winter kit can do. If leaves are a problem, cover the pool with the filter still in place. Maintain a decent chemical level, and run the filter occasionally. When the water temperature drops to 50° F, pick up a copy of our Pool Tips on Pool Winterizing, and follow these directions.

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