Can I Use Beach Pebbles in and Around My Koi Pond Waterfall
I want to create a water feature at the top of my waterfall, which runs into my Koi pond. I want to fill the water feature and some of the waterfall with pebbles from my local beach. Can I put them straight in or do they have to be treated with anything first, could they be harmful to my Koi?
Stuart Smith, Brighton
Answer: Someone has recently estimated that there are more pebbles on Brighton beach than people in the world; over 100 billion pebbles. You wouldnt think they would miss a few, but if they the bylaws are as stringent as they are on this side of the country then taking pebbles in any quantity from the beach is simply not allowed.
If however some pebbles simply arrived one way or another at your home and they did happen to look like pebbles from Brighton beach then they should just need a rinsing in fresh water to remove most of the salt. However, although they are mostly inert flint, they do come with a chalk coating that may affect the pH of the pool to a certain extent. If there is a sudden rise in the pool pH then this may have a detrimental effect on the fish, especially if they are coming out of a long torpid stretch at the back end of winter.
You could seal them with a water based epoxy sealant, but much better, I think, to spend your money on some nice river washed pebbles of varied size. The varied size, especially in a small beach effect with a few choice large pebbles, looks a lot more natural that the standard sizes of the British beach pebbles that line many of Britains natural beaches.