I have heard the rumour as well, but can't speak to the issue factually. I use X-tol as my favorite developer. One liter packs were too small and five liters packs too large. I now buy the five liter packs and evenly divide the materials in half, making two two and one half liter packs using a precision gram scale. I have never had a problem with the product. The mixed developer will last at least five months in a dark air tight bottle.(posted 8227 days ago)