Ive been gone from the planted tank scene for a while and this is my first post since coming back home. I love the way your tank looks and the placement of the rocks. The riccia more than likely hitch hiked in with your hc and its gonna be really hard to get rid of it. Riccia from my experience doesn't like Excel dosing. This is how I got rid of my Riccia but be very carefull because most plants do not respond well to Excel also. Keep up the good work and I look forward to seeing how your tank progresses.