If you have a leak in your swimming pool a dye test can be a quick and easy leak detection method that you can do using materials that you have around the house. You can purchase a special dye and applicator syringe from most pool supply stores however you might already have a dye tester sitting around and not even realize it. The red liquid and dropper bottle from old swimming pool water maintenance test kits are perfect for conducting a simple dye test for your pool.
The dye test itself is often misunderstood with many people believing that you can put a bunch of dye in the swimming pool and somehow have this find the leak for them. The actual way to perform a dye test is more complicated and less conclusive, but is still a common test performed by homeowners and professional leak detectors alike.
The concept of a dye test is to manually confirm whether a suspected leak area is in fact leaking or not. For example if you saw a mark on the liner of your pool underwater and suspected that water is escaping, you would conduct a dye test on this area. You want to spray the equivalent of four or five drops of red (or red food coloring) directly adjacent to where you suspect the leak is. The dye will predominantly stay together and slowly diffuse over one to three minutes with the gentle rocking of the water moving in the pool. On an area where a leak is present the red dye will still rock with the motion of the pool water, but it will also noticeably be pulled into the leak instead of just diffusing into the pool water.
The larger the leak is, the more apparent it will be that the dye is being pulled into the leak. This is a great test for around skimmer, return, stair and light gaskets where leaks will often occur.
Steve Goodale is a swimming pool expert and author located in Canada. His series of swimming pool, artificial rock and how to tutorials are regarded as some of the best in this niche industry.