yes, that is just what I have used it for in the past. If I was trying to do a larger space I'm not sure. Maybe in that case hydraulic cement would be best. I've used it after cutting the crack out larger with a diamond wheel but in the same instance I believe Vulcan would have been better. Now keep in mind that the surface of Vulcan does not get hard and stays soft for some time but its' bond to the cement and forms a leak proof joint. It too, works better after cutting out the joint.
One thing that I've been thinking about and haven't tried yet for waterproof type joints is the landscape caulking used for putting cement block retaining walls together. Last summer I was going to use this caulking to build a waterproof wall which was really a cellar window. The supply house told me that this would do the job and make it waterproof. As it turned out I found another method that didn't require that I block out the window.
I have used landscape caulking to build retaining walls and I thought it was real strong. One time I had some extra and built a little wall around a gas shut off that was just below grade after some landscaping. As luck would have it the gas company showed up a week later and couldn't use the shutoff because there wasn't enough of room. I thought OK, I give it a few whacks with a small hammer and break it free from the foundation of the house. No way, I had to break the block away and then later chisel off the caulking. I couldn't believe how strong it was. Much stronger than the solid concrete block and it cures hard in 24 hrs.
When you are repairing a leak from the inside it is easier than work I've done from the outside. The water pressure on the inside which is .434 lbs. per squ. inch per ft. of height is pushing in your favor insuring the caulking will not be blown out.
Now like I said Vulcan stays soft on the surface for a very long period of time so there may very well be another caulking which would be better suited for a pool type of repair. Their are many pool experts around so this should be an easy resolve.
I'll tell ya there are so many new products out there that are very good, you have to rely of a reparable supply house. I think some of these relatively new products are not known in Belize. For instance I've seen Spanish tile put down on cement with a silicon or latex caulking adhesive. Well I guess that was good several years ago but the new landscaping adhesive is so strong that I'm thinking of giving that a trial on a slab of cement. I'll bet it is better and will stand up to strong winds much better.
Many times, I believe products are used because they are readily available and not necessarily the best. Please understand that I do not claim to be an expert on concrete leak repair/bond and my life before I retired was in a different universe. Please if you find a good solution post it so we all can learn.
One last thought on your question. 50K or 500k gallons means nothing. It is the height of the water which is always .434 lbs. per squ. inch per foot of height. Many people can not understand this. It doesn't make any difference if we are talking about say, a 3' dia. circle or a 10'. It is the same although many might not think so. It is I assure you. It is the height of the water that makes the difference. Whether a 1" tube or a 10' dia. the pressure per squ. inch is the same.
ps Wizardofaahs that first sentence is misleading. It was a late night. Vulcan stays soft for weeks maybe months so in a swimming pool I don't think it would be very good. You need a hard finish. Maybe the land scrape caulking would work but it would not flex to any movement because it bonds read good and real hard in hours. Movement probably is not a consideration I would think. Again please ask someone who does this type of work routinely.
Edited by ragman (12/08/13 05:28 AM)
Edit Reason: ps
Somewhere on a beach in Belize