I bought a darkroom, which came with 7 1 liter bottles of KRST concentrate. As far as I know they are unopened. My understanding is that this stuff lasts forever, right?

All of the bottles are old plastic, and I don't think I trust them. When bending, they squeak a lot and I'm afraid one might fail at some point. Is it safe to open them all and pour them into 1 gallon jugs? Or, is this a horrible idea?