In Ground Vinyl Liner Pools first appeared in 1954 with the introduction of the first package pools using cinder blocks as a wall structure to support the vinyl liner. The liners they used were all one color, usually aqua, and all one thickness 20 mil. Time marched on and processes improved and package pools improved to the point in the early 1970’s manufactures were making pre-constructed wall panels of steel that would fit together
and liners now had patterns on them, making them more attractive.
The early vinyl patterns were cumbersome to produce taking many man hours to design and then translate to machines that would transfer the print pattern to the liner. For this reason liner patterns in the 70’s, 80’s and 90’s rarely changed. Then the computer revolution occurred at the end of the 1990’s, what that did for the vinyl liner industry was made changing patterns easier and less costly. Now liner patterns are changing like fashion, you see multiple patterns go away and new patterns show up every year.
What most people don’t know is the company that manufactures the vinyl with the print pattern is not the same company that manufactures the liner. They are two different companies. The companies that make the liner are purchasing the material from a vinyl manufacture then they take the material and assemble the liner you see in your pool.
The other thing that happened over the years is thicker liners became available. In more northern climates, where the weather gets below zero, they need thicker vinyl to stand up to the freezing and thawing. More recently the demand for 27 mil liners have increased. A 27 mil liner is 35% thicker than a 20 mil liner and better suited to handle abuse. The thicker liners resist punctures better than their 20 mil siblings. But, don’t confuse the thickness of the liner with the durability of the print pattern on the surface of the liner. The two are not related.
The pattern you see on the liner is just on the surface of the vinyl, the thickness of the liner does not have any effect on the print durability. The print pattern will, over time, sercombe to the effects of UV light and chlorine. The average life of a pool liner is about ten years if you take care of your water chemistry. At the ten year mark your liner will be noticeably faded, this is normal and it is what usually drives pool owners to change the liner.
To keep your liner in the best condition possible you need to maintain your pool water chemistry. The mineral balance of the water is critical to protect the liner against degradation. Water wants a certain mineral balance, if it does not have that balance it will go looking for something to satisfy its need in whatever is holding the water. Think of it like someone who is spoiled and throws a fit until they get what they want. That is what water is, out of balance. If the calcium hardness is too low for too long a period it will draw plasticizers from the vinyl and make the liner brittle to the point that if you step on it, it will crack. On the other side of the mineral balance is Total Alkalinity and pH, if they are too low for too long a period it will cause the vinyl to relax and stretch leaving wrinkles all over the pool. I cannot emphasize enough the importance of maintaining your water balance all year long.
A more recent development in vinyl liners is a new process by Latham Pool Products called UltraSeam®. This new seaming process makes the seams between sheets of vinyl virtually invisible. In addition the process makes the seam stronger than a standard seam.
When the time comes to search for a new liner the two things you want to look at are the thickness of the liner, you really want a 27 mil liner, and you want to get a liner with the new UltraSeam® construction. The liner pattern is really a personal choice, however, one point of note; if you have a pressure side automatic pool cleaner that runs on wheels you may want to stay away from dark liners printed on a white background. These cleaners sometimes will wear the print pattern off the liner surface and the white background will stand out like a sore thumb against a dark liner.
Welcome back for another semester of Pool School, now go out and have some fun in your pool until the next class.