If you have spent most of your career working exclusively on concrete pools, it’s crucial to learn about the distinct differences between vinyl and concrete before accepting maintenance jobs that involve package pools. Following is a closer look at the care and maintenance of vinyl-liner pools.

Water care

One of the biggest differences between vinyl-liner pools and plaster pools is how sensitive they are to sanitizers and other chemicals. Vinyl-liner pools can be much less forgiving when it comes to water care than plaster or pebble aggregate finishes. So it’s important for the water chemistry variables to be regularly maintained within the recommended levels.

Some experts warn that if there is anything under the recommended ranges — particularly calcium, pH and alkalinity — the water can become corrosive and destroy copper. If it’s over the proper ranges, scale formation can ensue.

  • Chemical options

pH 7.2-7.6
Total alkalinity 100-150 ppm
Calcium hardness 200-300 ppm
Cyanuric acid 30-100 ppm
Free chlorine 1-4 ppm

With vinyl-liner pools, you have to be more particular about the chemicals you use. Many techs say that chlorine gas should never be applied in these pools because it will lower the pH.

Others also avoid liquid chlorine, or sodium hypochlorite — because it can concentrate and bleach the liner if the product isn’t broadcast evenly throughout the pool.

Instead, they’ll opt for calcium hypochlorite. If you use cal hypo, though, first mix the powder well with water, broadcast it in the deeper end and be sure to brush the walls and floor afterward so nothing settles or clings to the surfaces. This should reduce the risk of the liner fading.

Others suggest placing the cal hypo in the skimmer to ensure even dispersal, though some warn that this may send too much concentrated sanitizer directly into the plumbing and equipment, which can damage them.

If the source water is high in calcium, techs recommend avoiding cal hypo and calcium-related products altogether. Why? Calcium will calcify the walls and cause the total alkalinity (TA) to increase.

In such cases, liquid bleach would be a good alternative, as long as it’s distributed evenly throughout the pool while the circulation system is on.

The use of stabilized chlorine products in vinyl-liner pools is something experts still debate. Some techs say they use them without repercussions, while others warn that these chemicals can harm the liner.

Trichlor, however, probably won’t be strong enough to get the job done if problems such as algae develop. And, be warned that trichlor floaters can bleach the liner if allowed to sit in one place for too long. Also, if your total alkalinity is already low, don’t use trichlor tablets because they have an acid base, which will force the TA level even lower.

For customers seeking an alternative sanitizer for package pools, biguanides work particularly well, though they can be expensive.

  • Chemical ranges

Using the right kind of sanitizers and chemicals is all well and good, but if you don’t keep the water balanced and all variables in the proper ranges, you can still harm the liner.
The recommended chemical parameters for vinyl-liner pools come in an array of ranges. The chart above shows a compilation of some of the most common ones.

When levels drift from these recommended ranges, the liner can be affected, depending on which direction the levels turn.

For instance, when the total alkalinity goes too far out of range, techs warn that the liner begins to break down and can lose its elasticity.

And while industry standards allow for a chlorine range of 1- to 4 ppm, some techs recommend keeping it as close to “1” as possible to avoid bleaching the liner.

The shocking truth

If service techs need to pay close attention to which chemicals they put into vinyl-liner pools, then it would follow that shocking the water in such vessels could be a dicey proposition. However, techs say that if you use the right products, it’s no more difficult than shocking the water in any other kind of pool.

For superchlorinating (aka shocking) vinyl-liner pools, nothing beats lithium chlorite, say veteran technicians. The advantages are that it won’t bleach the liner as readily or calcify its walls. Lithium hypochlorite probably would be the choice of vinyl-liner pool techs for their day-to-day sanitation chores if its high price didn’t make it cost-prohibitive.

If you choose to use lithium chlorite for shocking, mix the powder into a slurry and distribute it via the skimmer basket for even circulation throughout the pool.

Before shocking the pool, keep in mind the chemicals you have recently put into the water. Certain combinations of chemicals that, individually, will have no effect can cause bleaching if the concentration is allowed to remain high in the vicinity of the liner, techs warn. You should allow the chemicals to disperse throughout the pool through the circulation system after adding the second chemical.

Routine maintenance

Dirt and grime that accumulate at the waterline also can play a major role in shortening the life of a liner. Similar to a “bathtub ring,” the phenomenon usually is caused by airborne debris mixing with body and suntan oils and other organics, and collecting on the liner. It’s then baked in by the sun, which can cause the vinyl to dry and crack prematurely, especially in the area of the pool where sunlight appears the brightest and longest.

Care must be taken to wipe down the waterline on a regular basis. Use a plain sponge or one in conjunction with a recommended vinyl cleaner to stave off dirt and grime buildup.

Be careful what you use to wipe down the walls. A soft sponge is recommended. Anything abrasive can cause a problem with the liner. You can rub the pattern right off.

In addition, the technique you use when wiping down the liner is important. Don’t be overly aggressive. If you rub too vigorously, you can move the liner back and forth. Sand can work its way right through the liner. Some techs say that if the buildup  is so bad that you must rub it hard, maybe you just need to replace the liner.

If grime has accumulated, it’s important to use only cleaners approved by the manufacturer for use on vinyl. Never use petroleum-based products because they can rapidly deteriorate vinyl. If you decide to go with a vinyl cleaner, though, test it in the pool first. Do it in an inconspicuous area to ensure there are no surprises.

Regular brushing is recommended to keep excessive chlorine from clinging to the walls and fading the liner pattern, experts say.

Once the waterline is clean, it’s a good idea to add a layer of protection. Many products that are not petroleum or alcohol-based are available. They will protect the liner from further buildup.

Try not to drain the pool unless you’re planning to do some major repairs or refitting. But if you find that some draining is unavoidable, do not lower the water less than 1 foot in the shallow end. If water pressure is removed from the liner, even for a short time, it could shrink and become unsightly, or possibly tear around the fittings and in the corners.

When it comes to cleaning equipment (brushes, vacuums and even automatic cleaners), be sure to choose those suited to vinyl-liner pools. Every implement that is made for cleaning swimming pools is also made in a vinyl-liner form. As long as you use the implements made for that type of pool, you should never have a problem. For example, a gunite pool brush has square edges while a package-pool brush will have upturned, rounded edges.

If the pool has an automatic cleaner, or the homeowner is in the market for one, be sure it’s a brand designed for use in vinyl-liner pools.

Use a vinyl-liner vacuum, one that has brushes instead of wheels. While the liners are surprisingly durable, you still want to be careful, especially in the corners.

One final tip to help your brushing and stain-fighting regimen: Keep the water level as high as possible. That way, there will only be 2- or 3 inches of exposed vinyl that you’ll have to keep clean.