we are having our pool resurfaced soon and, although none of the folks who gave us quotes even mentioned this, we think we may have to replace some or all of the waterfall that flows from our spa into our pool. currently the waterfall is just glass block with a crappy plastic ledge on top. the reason we need to replace it (we think) is that two of the glass blocks are growing algae INSIDE the block. it's a little easy to miss because it's on the top blocks closest to the plastic edge, so maybe that's why the pool folks haven't mentioned it.
anyways, i don't particularly love the glass block, but a stone waterfall would look out of place since there's no other stone in the pool area. what other materials are available for waterfalls?