Consider the following statements about the role of biofilters in a Recirculating Aquaculture System (RAS):

1. Biofilters help remove solid waste, such as uneaten feed and faecal matter, from the water.

2. Biofilters convert toxic ammonia excreted by fish into less harmful nitrate through the process of nitrification.

3. Biofilters are used to deliberately enrich the water with phosphorus, to promote plankton growth as supplementary fish feed.

How many of the statements given above are correct?