Those buckets that you can get at Home Depot are made from the same plastic as the food grade buckets. HDPE (high density polyethylene). The cloudiness that occurrs with Star-San is not related to its effectiveness, it is related to the mineral content of the water that it is mixed with. The main factor with regard to the effectiveness of Star-San is its pH. Star-San is a blend of phosphoric acid and dodecylbenzenesulfonic acid. This combination of acids provides a sanitizer that is unaffected by excessive organic soils. As long as the pH remains below 3, it is still effective. Even if the pH rises above 3, it can just be "sweetened" up with some more concentrate to drive the pH back down. I use some cheap test strips to check the pH and have kept batches of Star-San for up to 6 weeks. The only reason I dumped them was for piece of mind, and that I felt that I got my monies worth after 6 weeks of using the same batch.
How long is the One Step solution good for? Many factors come into play in answering that question. One Step works by producing hydrogen peroxide in solution, so the most important thing is to keep that peroxide. Peroxides are degraded by organic soils, light, and heat, so if you keep your solution away from those things, it will stay better, longer. In a closed, dark, and clean container, the solution will last up to 1 week. In a closed, clean container in a refrigerator, the solution is good for over a month (but let it warm up before you use it).
I can confirm that Iodophor looses its effectiveness after 24 hours and should not be reused. I sent an email to National Chemicals Inc., the maker of BTF Iodophor, regarding the shelf life of Iodophor that has been diluted to a working solution. A Dr. L. Charles Landman responded and explained that there are a number of things that work to degrade the products' effectiveness. Chlorine in the mix water and organic soils were the two mentioned first, but Dr. Landman agreed that both sunlight and exposure to the atmosphere are also factors.
Iodophor is very stable in it's undiluted form, but will begin to degrade slowly once it has been diluted to a working solution. The color of the Iodophor solution is a rough guide to it's effectiveness as a sanitizer. If the solution still has its amber color, it is most likely still active. It is recommended that a fresh solution should be mixed when the color fades or after 24 hours. I hope this helps.
John