Found the leak! How to fix missing tile grout?

[Deez]

I don't know how or when this happened but my pool suddenly started losing a lot of water, but the water loss stops when the level reaches the bottom of the waterline tile. It wasn't too hard to find this leak once I started looking. Now I need to know how to fix this. Is there a specific type of grout that is best to use in a pool? How can I seal up this major leak? Thanks!

 

[Melt In The Sun]

Did you do a dye test on that spot, to see if it's actually leaking? That would be very unusual....grout in itself is not waterproof, and unless the shell is cracked there's nowhere for that water to go anyway. How about the skimmer, could it be leaking there?

 

[Deez]

I haven't done a dye test. I just know that when i fill the pool up to the middle of the tile, the water will be back to the level shown in the photo in about a day. There is still barely enough water for the pump to run and the level is holding steady at the bottom of the tile for a couple days.

I assume the dye test is a little bit of food coloring to see if it goes into the suspected crack?

Even if this isn't the leak, what can i use to close up the gap so that it looks nice?

 

[Deez]

Would the 'Patch-It' stuff from leslies be a good product to fix this with? Or some sort of epoxy and or caulking?

http://www.lesliespool.com/cgm-patc...-for-concrete-pool-repairs-3-lbs/patch-it.htm

 

[Melt In The Sun]

I'd just get a tube of polyurethane caulk in a matching-ish color and use that. It should look nice and keep water out. Yes, the dye test would just be some food coloring.