Help IDing this light brown/white fluffy algae

spockagain34 · Sep 7, 2023

I’ve got a new 92 total system volume tank set up and cycling since April 2023.

Water parameters have been holding pretty stable:
Alk 7.5
CA ~450
Mg ~1360
Nitrates are negligible

The tank seems pretty clean except for this weird fluffy light brown/white algae substance that is growing on the rock. Anywhere that coralline algae takes hold seems to keep it at bay. Any ideas of what this is and what, if anything I should do about it?

malacoda · Sep 7, 2023

Looks like hair algae to me. The tank is young. Pretty normal to experience an 'ugly' stage — with various algae, cyano, etc. — right around the 4-5 month mark.

It can last anywhere from 3-6 months. Especially common with tanks set up with dry rock (and can last longer in such setups as well).

Boosting nitrate and phosphate a little ... 3-5 ppm NO3 and .03-.09 (or so) PO4 ... may help a bit. But really time and patience are usually the real key.

Lavey29 · Sep 7, 2023

Agreed, bottomed out nutrients will lead to problems and dead coral. You will have a variety of ugly phases over the course of the first year. Get diverse cleaner crew and correct your parameters.