Steve, I know my mg is a little low. I does Tropic Marin Bio Magnesium to attempt to raise it. With 400 + gallons you can only imagine that I am dosing mg by the pound.....
ttt = to the top... posts get lost quick around here. LOL
Some rocks are held by zipties, but most are held by gravity... I notched some of the rocks with a hammer and chisel to get them to fit better.