My refugium was started with miracle mud over 2 years ago. After the first year, the LFS that maintained the tank replaced the miracle mud with sand. That was a disaster! Growth in the refugium slowed and the main tank suffered. The main tank slowly spiraled downward until I finally had to try something. Hair algae was taking over.
About a month ago, I wised up and vaccumed out the sand. Refilled with miracle mud. I can tell a huge difference. More growth and more pods.