Dragons breath algae
 

Is it possible that this macro algae is causing this black looks like diatoms, to grow on my glass. I never get brown or green algae to grow. Also the sand will turns brown within 24 hours of being stirred up. If I don’t stir up sand it will start to clump within a couple of days. Tank numbers are phosphate 0.04, nitrate 0. Mag 1250 Alk 8 dkh, cal 460. Temp 78. Lighting Chinese black box’s run blues at 80% whites at 10%.

Plants don't cause algae, but they can bring it in to your tank, if coated in it. You can clean new macros with a 20-1 bleach solution to prevent this. Sounds like diatoms on your sand. New tank?

Tank is 3 years up and running. I do have a sump and Refugium. Lots of small feather duster worms grow there. I occasionally clean it out since detritus seems to collect there a lot. The worms love it. I run GFO to lower phosphate and dose nopox daily. Just want to find source of this black algae . Coralline is present on some rock but not flourishing like I would like to.

Black stuff might be cyanobacteria. For that, I'd recommend a week or two of aggressive daily manual removal, followed by chemiclean treatment (or erythromycin), a 3-4 day blackout (wrap the tank), manual removal of any remaining, and finally, a large water change.

Doing just one thing doesn't usually work. I have found that cyano (and dinos) need to be weakened before delivering the knockout blow. That's what worked for me.

Mike thanks for the advice. Did the chemiclean treatment . Removed collection cup from skimmer and turned off UV light for 3 days. Only had on blue lights 1 hour a day for fish feeding. Finally did a 25% water change for me that was 30 gallons. Success the tank looks great all corals look fine, sand is white again no traces of cyano or black looking diatoms on glass.

My pleasure! I'm glad to hear you beat it.