Black Lava is an attractive rock in its own right so not only is it beneficial, it is also ornamental too. They look very natural and stack very well indeed. Some people comment that it is like as if the rock has glue on it as it stacks together so well. It is so versatile and you can really have some fun playing around with different pieces and creating various shapes and constructions. It is popular for creating a cave effect making it a perfect refuge for certain fish and shrimp.
An anearobic environment is created inside the rock as beneficial nitrifying bacteria consume all the oxygen in the water. Within this anaerobic environment inside the rock, denitrifying bacteria consume the nitrate and produce oxygen and nitrogen. We all know how nitrate in the aquarium is bad news for fish and shrimp so Lava Rock really is the most natural and best way of removing nitrate.