I had wondered about the concertina bottles leaking, at the moment I only use them for my dilute Selenium and working solutions of fixer and paper dev,
This type of bottle is the worst possible choice for two reasons. The soft polyethylene that they are made of is very permeable to oxygen and not good for developers. Because of their design they are impossible to clean should anything get on the inner surface. Soft drink bottles made of PET plastic are a good choice and are virtually free.
A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.