Chia seeds absorb 30x their weight in water? I really don't know how psyllium compares to chia seeds with absorption of water or toxins. Psyllium absorbs toxins and increases fiber thru the intestinal tract. I think the psyllium is used for the muscilangenous properties it has as well as the toxins it absorbs. I do't know what the mucilagenous properties of chia are. Maybe we don't want to absorb so much water thru the intestinal tract. I don't know how much of the chia seed you would use before it was too much. The bowels need water to move the food along or it will be absorbed from the rest of the body. That's the principle the Fleet enemas are based on and why they work, but they can cause a lot of abdominal pain if a person is dehydrated.
Chia seeds are very high in nutrition. They might be better sprouted and eaten like that.