Long time since I did an update on this thread.
Here is a picture of a huge spring in Kimpese 200km west from Kinshasa. Water comes out directly from the sand, water is cold around 24C and is crystal clear water. Substrate is cover of one type of plant but I don't know which one !!
Darrel or someone else ??? Hahaha
Sorry he didn't take close up pictures of the plant.
Here are some picture of that beautiful place.