My pool is about 1-1/2 years old. I have never had any issues till now...thanks to following the advice on this site for general pool care/chemistry. Just today I noticed a relatively small bubble in the liner at the water line. I know it wasn't there a couple days ago as I cleaned the waterline. The bubble is about 1-2 feet wide and extends from near the waterline down the wall about 18". It also extends an additional 3-4 feet along the waterline, but only goes down about 4-5 inches Below the water level. The bubble does not stick out very far, so it is hard to see until you get close to it. Also, the bubble seems to have a very distint edge and no evidence of the liner being soft even a few inches away in any direc tion.
I am trying to figure out the cause. The water level hasn't changed (at least not yet). I have never noticed the issue previously even with large amounts of rain despite having clay soil and a flat yard. And it hasn't rained that much in the last week, so I can't imagine I suddenly developed a ground water problem. I have not pulled the liner off the track to test the water (salt pool so I should detect salt if from the pool)
I looked in the general vicinity of the bubble and didn't see any obvious punctures or tears in the liner. Confused about where I should be looking. Would the leak be near where where the bubble is located? Or, could it be coming from further away and following the water line or coming up from a leak on the bottom? I intend to get some food coloring to look for leaks more closely, but I assume this be difficult to find if it a slow leak.
Thanks for any advice/guidance that anyone can provide.