Aquarium Pharmaceuticals, Inc. puts out a salt test kit. It's under their Pond Care line, product no. 163. I use it and feel it it's good for my everyday every tank needs. I have a goldfish tank, and a small koi pond and four brackish tanks with different salt % needs, and the kit helps keep a piece of mind about salt use. Also I have plants in all of these set-ups too. JiM C.