Help Identify Algae and What’s Causing It

[discretekarma]

Hi! I have several tanks connected making up about 250 gallons total. They’ve been set up for about a year and a half. The corals and livestock have done very well but I’m constantly battling several types of algae (pictured). I have coral+ T5 bulbs which are frequently replaced and viparspectra LED lights set to about 30%. 
 

I assume it’s either not enough clean up crew, lighting, or too much/little of a nutrient that’s causing it but would appreciate some advice.
 

Green/brown hair (cotton looking) algae and a green lettuce looking algae. Hopefully the pics load ok. Thanks!

[lynn.reef.nerd]

My guess: Ulva, Bryopsis. 

Some places I like to get information about macroalgae,etc. 
https://www.reefcleaners.org/aquarium-store/plants-macroalgae
https://melevsreef.com/creatures/category?id=KWWb6Q2lxzTdLE3pxQWs

If you have tangs, i'm surprised they have not destroyed the ulva. 

[discretekarma]

Thanks! I’ll check out the link.
 

I only have a tang in 1 of the 3 tanks. The tank that has it the worst only has a gold nugget clown pair and a small wrasse. 

[DaJMasta]

The second could be more standard filamentous algae - hard to tell out of the water.  Bryopsis looks sort of fern like (stalk with lots of branching parts on opposite sides to make a flat frond), whereas other algaes generally just look like strands.

 

I think you have the right idea for the causes, but to add to the potential list: perhaps there was some nutrients that leeched out of the rock or that your lighting cycle is too long.  My preference is usually carbon dosing to get rid of things provided the nutrient input is reasonable, but bryposis can have more specific treatments if it's that, and maybe just more clean up crew can keep it in check.  Something like a sea hare could also just bulldoze quite a bit of it, though it may eat it too quickly to manage the problem in the long term vs. just eat everything and starve.

[discretekarma]

Thanks for this info. After looking at pics online, it definitely seems to be standard filamentous algae in the second pic. It is indeed hard to tell in the pics but I can tell by comparing pics online. I’ll start by increasing my cleanup crew, adjusting my lighting cycle slightly, and replacing my carbon.  

[mogurnda]

The first one is definitely Ulva.  Tends to thrive in higher nutrients (seems to especially like NO3 above 20), and likes lots of water motion.  Some tangs will eat it, some won't, but it tends to fade away at some point, probably when some limiting factor runs out.

 

The second could be either Derbesia, which is the usual "hair algae" or Bryopsis. A couple of ways to tell the difference.  In the water, Bryopsis generally has side branches that make it look feathery.  The easiest way is to feel it.  Bryopsis pennata, which is the usual species we deal with, feels coarse, whereas Derbesia feels like soft, squishy felt, with no obvious texture. Bryopsis also likes high flow, so you will often see it growing on your return nozzles. 

 

Bryopsis likes the conditions we give corals (low nutrients, high flow) whereas Derbesia tends to get going when nutrients go up (especially PO4) or there is a major disturbance.  This generally means that Derbesia will disappear when conditions settle down, but it can be a headache for months before it disappears.  There are many ideas about dealing with Bryopsis, many of which are worse than the algae.  I just let it grow on the nozzles and let the urchins eat it everywhere else.

 

You have not posted about your tank conditions, specifically NO3 and PO4.  If I am right, your NO3 will be somewhat high, and PO4 may be as well (but may not be, because the algae may be mopping it up).

 

The only grazer that can be guaranteed to deal with these kinds of algae would be an urchin.  Most species of snail won't touch Derbesia, and the only hermits that eat it are Mexican red legs (not the usual scarlets).  I am extremely fond of urchins as grazers, and the rock-boring urchins (Echinometra sp) will not bulldoze your corals.  

 

My advice would be to be a little more aggressive with your water changes, feed a little less, wait the problem out, and maybe add an urchin.  Do you have a refugium? 

 

**The above advice comes from many years of reefing, and, more importantly, more than five years of developing methods for culturing filamentous algae.

[MaeganWink]

@mogurnda I didn't know urchins eat hair algae?

[DaJMasta]

They do!  Pretty effective little snowplows and primary herbivores on a lot of reefs, but there are some disadvantages that stop people from going that route.

 

While they eat algae all day, there are at least some species that make no distinction between microalgae, macroalgae, and even coralline algae.  As they get bigger, they also can fit between fewer gaps than smaller snails or bigger fish, and they are fairly strong so they can push over frags and things.  There are also some short spine species that will grab on to bits of their surroundings as camouflage, which can include corals and other things you may not want ripped off their base and moved around the tank.

I've got a bit of a hair algae thing going on in my tank and the urchins seem to be oddly selective about the areas they eat, but when they do it goes completely clean, so hopefully they will get to most of it eventually.  I've seen similar cleaning results with several kinds of snails, but again it sort of depends on where they are when they want to start going at it, so the results can be patchy, and generally the impact of a single snail is less.