IM fusion sump bottom chambers?

[Jdubyo]

I decided to peel off the back of my tank due to chasing aiptasia and seeing some in my sump. After peeling it off I noticed there are chambers underneath both of the baffles where the water would flow in. there is absolutely no flow in this area and mine had about an inch of detritus on both sides. I'm not sure how I haven't ever known about this.

Is there any logical explanation for these chambers? why would the baffles not go all the way to the bottom?

 

[ReeferReefer]

From what I have seen it is designed to give you return pump some extra water incase the levels get low. I would toss a bag of seachem matrix on each side and clean it out a few times a year.

 

[Esage]

From what I have seen it is designed to give you return pump some extra water incase the levels get low. I would toss a bag of seachem matrix on each side and clean it out a few times a year.

This is what I did