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.