It's the action of chelation that may deplete minerals apparently, due to the stress/movement of mercury and interrupted sleep. The chelators themselves do not have any significant depleting effect on minerals - at least according to Cutler.

I used to feel exhaused from chelating and agree that it is important to supplement vitamins/minerals regularly, regardless of active chelating or not. That plus the diet to support the body's immunity, reduce excessive yeast levels and help the body absorb nutrients properly. Without the diet in place, vitamins/minerals were not very effective as I was so sick I was unable to ultilise them. Candida and excess toxins I dare say were the culprits.