Turf Algae or plain old GHA?

[madadium]

Hi all,

I've been having a heck of a time getting rid of this algae (pics attached). Nitrates and phosphates are not detectable (API test kit), and I've been brushing the rocks / siphoning out the gunk once a week for the last 4 weeks. It continues to grow back. My CUC (2 turbos, 3 astrea, 6-7 hermits, 1 tuxedo urchin, 1 emerald crab) don't touch it. Does not blow off the rocks easily and collects detritus. It's not growing much at all in the highest flow area of my tank (in front of mp10).

About my tank (8 months old): 32 gal biocube w/ nanobox LEDs, running chemipure blue and poly filter in media basket, chaeto growing nice and fast in refugium. Ca/Alk/Mg = 450/8.5/1300. pH ~8. Temp ~80.

Any advice on what you would do here? I'm getting fantastic coral growth (especially sps) so I'm not sure I should do anything drastic. I've tried lights out for 3 days (twice) and didn't affect it much. Thank you for any advice.

 

[saltyfilmfolks]

Does it come off in turfs?
Turf algae does.

 

[madadium]

Does it come off in turfs?
Turf algae does.

Tufts? No, not really. I'd physically have to pull the strands it off the rocks, blowing it off won't work. Brushing off seems to be most effective.

 

[saltyfilmfolks]

Tufts? No, not really. I'd physically have to pull the strands it off the rocks, blowing it off won't work. Brushing off seems to be most effective.

Then it’s not a trurf alge. It’s rooting in the rock.
Turf comes off like sod.

 

[madadium]

If it is GHA should I just keep doing what I've been doing to fight it?