I'm forming a red/brown algae on the sand. I've been stirring it up and within a day it's coming back. When stirred it clumps up. My calcium level is 420. Could it be too high. I have alot of softies, 240 lbs of rock along with a hand full of fish.
No,calcium at 420 which is a good level to keep your calcium at is not the problem. It sounds like cyanobacteria, how old is the tank? It is a common problem in new tanks. It tends to go away on its own as the tank matures, but increased flow will help reduce it. Please list all your water parameters for better advice.