ident Algae how to treat?

[Myka]

Ya, get that RO sorted out so that you're getting less than 2 ppm tds.

Get some sand sifters for your sand. An Orange Lip Conch or a Fighting Conch would be a good choice for a 45g tank. Sounds like trapped sulphurous areas in the sandbed. You can fix it by stirring the sand yourself, but only do a 2x2x2" patch each day. Release too much in one go and you'll poison your tank. The black patches will stink too.

You definately have excess nutrients in the tank, so take a good look at what's going in there.