Actually, the light may be the culprit. Believe it or not, a light niche leak may not be readily apparent, even with dye. Mine was leaking about 1 inch per day, and showed nothing on the dye test that I did myself (i didnt pull the light, just checked around the fitting). My pool leaked with the pump on or off, leaked with all 3 returns, skimmer, and suction plugged. And, no wrinkle in the liner; that usually means a liner tear. My pool guy came out and looked over the situation. He thought it was where the cable went thru the back of the niche into the conduit. That can crack and cause a leak. He immediately pulled the light and found that the plastic niche itself was cracked. Bit of epoxy and some putty; no more leak. The lesson is dont trust the dye test when it could be the light niche.
Pulling out my hair with a pool leak!!!
- Thread starter phild
- Start date
I was assuming the light was pulled, and the back of the niche checked. Phil, is that what you did? If not, certainly do 
phild said:
After running for 24 hours the level dropped about 1.2 inches. Maybe .5 inches less than with the main/skimmers open.
bk406 said:
Hi BK.
This is what I suspect, but don't know for sure yet. My lights are stilled installed and when I use food coloring around them, there is nothing obvious.
Melt In The Sun said:I was assuming the light was pulled, and the back of the niche checked. Phil, is that what you did? If not, certainly do
Hi Melt,
No, the lights are stilled installed.
I would be glad to do what you are suggesting, but I'm unsure of the process as the lights are about 18" or so under water. So, I should take the lights out and set them on the deck, float some food coloring in the cavity and stick my head under to see if its leaking?
What does a 1 inch or so per day look like?
Yep, you just unscrew the light housing and pull it out; there should be enough cord behind it to lay it up on the deck. Then it's just as you guessed; squirt some food coloring in there (especially around where the cord goes through the niche) and see what happens.
If all attempts fail to pin point the leak keep in mind that the water will only leak down to the height of the breach. Obviously if the leak is at the bottom of the pool this is not a great option but if other attempts to fine the leak don't work what else is out there. This would not address multiple leaks either. Hope you fine it before you have to resort to this method.
Actually, sometimes the pool wont leak down as far as the breach. It can depend on the hydrostatic pressure on each side of the pool. For example, mine leaked down over the winter, but never got as low as the light. Once the pressure equalizes, the water stops going out of the pool.