Wondering if anyone around here uses an extra stage on their ro/di filters? What's in your extra canister?

I just ordered an add-on canister from buckeye with the idea of running 2 di canisters, both with color-changing di media. But, I also say they offer a silica di mix.

I know Solid had like a 50 stage water filter system (ok maybe a little less than that) but he was dealing with chloramine in the Corpus water.