Underwater Pond Crack Repair

"A 500 gallon cement pond formed a 2-foot crack just after being cleaned and refilled. The width of the crack ranged from hair-line at its ends, to up to 1/16" at the widest. The owner estimated that about 75 gallons of water per day was leaking through the crack. He did not want to drain the pond again, so I suggested we repair the crack in-place, with the RayCrete I had given him to use to fill the FIRST crack which occurred a year ago. (The first crack is still holding strong.) The new crack is within a couple inches of the first crack, meaning the bond strength of the RayCrete used to repair the first crack exceeds the structural strength of the concrete pond!

I opened the old RayCrete and found it to be creamy and smooth. I mixed about 2oz and applied the material to the crack under the water, the goldfish and Koi within one foot witnessing with curiosity. I made no special effort to remove the green, slimy algae that surrounded the crack on the pond bottom. Using my index finger, I dipped into the RayCrete mixture and applied it into the crack.. The RayCrete stuck well into the crack. Some lumps came off my finger and floated, but for the most part the material clung to my finger or the pond bottom, which was slimy with algae.

A few minutes after getting out of the pond I noticed all the fish examining the crack very closely, as if they were inspecting my work. I hope it meets their approval.

The pond was repaired Tuesday Sep.9. As of Thursday, Sep 11 the fish are all fine and the pond stopped leaking!.

I know of no other substance that is as safe to use and versatile enough to perform the same task."

-John Powers, San Diego, California