I don't have an answer for you, but I do have many questions, and maybe that will help the discussion along:
How are you measuring elasticity of a hydrogel, in a high school classroom-type environment?
How does potassium permanganate work on the hydrogel to increase elasticity? You start out wanting to test metal ions, which one do you mean, potassium, manganese, or the permanganate ion?
Can you give me details on the atomic level of what happens with Potassium permanganate and sodium alginate hydrogel that makes it the highest elasticity.
I'm betting not. Its very hard work to understand chemical processes "at the atomic level." People don't always do that for mundane applications. We tend to study things in bulk, from multiple conditions, then try to extrapolate what's happening at the lowest levels.