Divots on Bottom of Pool

by Marty
(WI)

We recently noticed several large divots in the bottom of our pool liner in spots where it seems the sand base has washed away.

They are about 5-6 feet from the edge of the pool and they were not there the last time we were in the pool. Some of the divots seem to be in a trail as you would think water would flow.

We also noticed that we can see the outline of one of the bricks which one of the side supports sits on in the liner near the beginning of this trail. We do not see any evidence of a leak from the outside of the pool (wet ground...)and the water level has not gone down that we can notice.

Does this trail of divots necessarily mean that there is or was a leak in the liner causing water to get out and wash this sand away or are there other explanations for the sand to wash away under the liner? Is there a way to find a hole that you can not see?

I do not see any air bubbles coming from the bottom anywhere. I believe that in order to repair these divots, I will have to drain the entire pool, pull the liner back and replace the sand that has been washed away. Do I have any other options?

Hi Marty.

It sounds to me like the divots are caused by bugs, ants or something under the liner, not a leak in the liner. This does happen on occasion. I would start by going around the outside of the pool with a good dose of Green Day ant killer. If the problem is bugs, this will get rid of them.

To fix the pool you will need to drain the pool. This will need to be done fast, before the liner has a chance to shrink. When the water is down to just under an inch you should get started. It's best if you can leave just a touch of water in the pool, enough to keep the liner from shifting. You should leave the skimmer and return on the pool, this also helps to keep the liner in the proper position.

You can pull the liner back, with one person holding the liner and another person filling in and smoothing sand. Immediately put the liner back into position and start refilling.

If you have any doubts about the cause of the divots, you can get under the liner. Have someone pull the liner over your head until it is dark. Any holes will look like little stars, if there are any you will see them.

Small Depressions in Sand

by John
(PA)

I recently installed a DoughBoy 16'x24'x52" AG with stretchable line with no deep end. There are some shapes on the bottom in the shape of the tamp tool used on the sand. Can these be smoothed out while the pool is full? Underwater roller?

Hi John.

I would not put a roller in the pool, that does not sound like it would be good for the liner. There is very little you can do with a pool full of water, the sand moves very little. With about six inches of water in the pool the sand moves a lot better and you could do a lot of smoothing.

When the time comes to change the liner for the first time is when you can really get it smooth. Use a push broom over the sand and you can make it perfect. Because the sand is well packed from the weight of the water over the years, it tends to stay much smoother, than a new install.

Using the liner installation instructions on this page you will have a pool you can enjoy for many year into the future.

Expandable Liner Installation

Small Bumps in Above ground liner on the Wall

Our pool is one year old (Sandy Point Artesian 24' x 52") and i just noticed a series of bumps on the liner on the wall.

The liner does have a lot of wrinkles on the floor and divots all over the floor and around the bottom of the wall but none are leaking though.

It looks like its about the height of the water level that was during the winter, so like 3 feet up from the ground.

There are many of them but they are all disconnected and separated from one another and cover about 15 feet of the pool on one side only and its about a 6" high area, the rest of the liner around the rest of the pool is fine.

When I push on them they flatten out then just come right back in the same spot as if its a wrinkle.

I have no idea what this is, I was thinking if its a leak water should go down the wall, right, and when I press it it should not pop back up? I tried looking for tears or something but I can't find anything and the pool is not loosing water.

Hi.

If I were to guess I would say there is some corrosion developing on the wall in this area. It is possible it's caused by a small leak in the liner.

A leak high on the wall, like maybe from a skimmer or return, will not usually make it's way down the wall to the ground. There is a lot of pressure pushing against the liner, the farther down the wall the more pressure. Water will try to find an easier way out.

An easier way out may mean rusting a hole through the wall and escaping that way. If the pool were mine I would find out what the bumps are, sooner rather than later.

Drain the pool down a foot or so, pull the liner back and have a look. If it is wet behind the liner that needs to be fixed. Even if it means replacing the liner. Liners are a lot cheaper than sidewalls, and a lot easier to replace.

More than likely you will not need to replace the liner, but you should find out what's going on.

Roots Under My Doughboy

by Bill
(Oceanside, CA)

I have a 32 by 16 foot oval Doughboy pool with a number of pine roots growing under the liner. I can't decide if I should ignore them or try to remove them. The liner is about 5 years old. Any advice would be greatly appreciated.

Sincerely, Bill

Hi Bill.

I have seen forests growing under pool liners when I have removed them to install a new one. It is not at all uncommon.

I have seldom seen tree roots damage a liner, they tend to grow horizontally, not vertically. So my suggestion would be to leave it alone until you need to change the liner. At that time you can cut them all out, add a little fresh sand, and start over again.

Because of the age of the liner, it would be difficult, if not impossible, to drain the pool completely and be able to reuse the same liner. It will shrink and become brittle, as soon as it is emptied. So plan on replacing the liner when these repairs are made.

If the roots are not posing any problems and do not appear dangerous to the liner, I would leave them be for now. If they are getting so big they get in the way of cleaning, or you are worried about cutting the liner as you clean, you may consider removing them now.

If there are sharp points you feel might puncture the liner, again, it might be time to remove the roots. But if you are just starting to notice them, and they are not posing any real problems, you probably have plenty of time left to get a few more years out of your existing liner.