Complete Aquatics Waterfall Foam DIY 16 oz

This expanding foam is perfect for setting and sealing the rocks in your waterfall or stream. The foam expands and hardens to fill spaces, so you can make sure the water flows over your rocks, not under them. The foam is colored black, in order to more easily disguise it in your water feature. Some of the pros, though, will toss some dirt onto fresh foam to camouflage it more.

Safe for fish and plants.