Sealing Porous Coral Rock for Waterfall

[NiftyFifty]

Has anybody had success with sealing coral rock? I’m not sure if I’m posting this in the right place. Maybe I should attach it to my original post about my pond?

Anyway, I just realized that the rocks for waterfall I am rebuilding might actually be coral. I assumed they were lava stone because we are so close to Idaho (I’m in Salt Lake City, Utah).

Over the last 2 weeks, I’ve been placing the rocks for the waterfall. It’s taking me forever because I’m moving them myself. At any rate, last week it occurred to me that even though these rocks were used in the original waterfall, I should test them to see how the water runs on them. Much to my chagrin, the rocks are like a sponge! How in the world was this ever a functioning waterfall with these porous rocks???

As I said, I had assumed I was dealing with lava rock, but during my experiment with running water over the rocks, I thought to carve out a bowl and trenches in the rock to see how difficult it would be to carve where I needed to. I was puzzled because the rock was so easy to dig into. Then it hit me — this might be coral rock.

As an experiment, I covered the bowl I carved out of one of my rocks with sodium bentonite. With a thick enough layer of clay, the water doesn’t seep through the stone, however, once the water evaporates, the clay cracks and water runs through the cracks in the clay. I guess you have to keep it wet for the sodium bentonite to work?

So, I’m desperate for suggestions for sealing the rocks so that water will run over them rather than soaking into them.

Thanks!

 

[Lisak1]

I think you’re fighting a losing battle to be honest.

Can you post pics of the original waterfall?

 

[j.w]

Has anybody had success with sealing coral rock? I’m not sure if I’m posting this in the right place. Maybe I should attach it to my original post about my pond?

Anyway, I just realized that the rocks for waterfall I am rebuilding might actually be coral. I assumed they were lava stone because we are so close to Idaho (I’m in Salt Lake City, Utah).

Over the last 2 weeks, I’ve been placing the rocks for the waterfall. It’s taking me forever because I’m moving them myself. At any rate, last week it occurred to me that even though these rocks were used in the original waterfall, I should test them to see how the water runs on them. Much to my chagrin, the rocks are like a sponge! How in the world was this ever a functioning waterfall with these porous rocks???

As I said, I had assumed I was dealing with lava rock, but during my experiment with running water over the rocks, I thought to carve out a bowl and trenches in the rock to see how difficult it would be to carve where I needed to. I was puzzled because the rock was so easy to dig into. Then it hit me — this might be coral rock.

As an experiment, I covered the bowl I carved out of one of my rocks with sodium bentonite. With a thick enough layer of clay, the water doesn’t seep through the stone, however, once the water evaporates, the clay cracks and water runs through the cracks in the clay. I guess you have to keep it wet for the sodium bentonite to work?

So, I’m desperate for suggestions for sealing the rocks so that water will run over them rather than soaking into them.

Thanks!

Wondering if there is some kind of a sealing spray that is not harmful to the water? Just guessing but it seems like something like that might work. I just looked online and this seems to be pretty impossible for what you want to do. But then, never say never!