Well then... make a matrix of such fuse-containers? (say every 20cm or whatever) I guess manufacturing such a matrix would be pretty expensive though, you'd need to carefully automate its production I think. It would also definitely interfere with flow of fluid in the tank.
Easy to imagine protective mechanisms in hindsight, now imagine you have to build a system for every tank of every chemical in the world
I was thinking multiple long skinny tubes with etchings that make them more likely to split lengthwise. Maybe with a spring loaded/powered agitator so when the tube breaks there's some mechanical flinging/mixing of the inner chemical.
But I'm not a chemical processes engineer, so I don't know how much mixing is needed. But the existing emergency plan was to inject the the chemical through a single valve, so it seems like the dispersion and mixing requirements in this case seems to be low.