Red algae won't die

[FingersCrossed]

Earlier this year I had a lot of fuzzy/thick red algae on most of my rock and aquarium wall. I was able to remove from the wall (physically removed) and get a lot off the rocks (turbo snails), but it remained as a thin layer that I couldn't remove and the snails didn't seem to want to eat. The snails then all died off pretty quickly.

Water parameters were all fine and not much nutrient added to tank -- 120G tank only had 3 small fish that I fed lightly. I also dosed with Vibrant bacteria, but don't know if that helped or not.

I moved the fish to another tank, and then did a 9 week total blackout. (No coral, fish, or inverts in tank.)

I just uncovered and found that the algae is still there. It's perhaps a bit less dense, but it's still on all rock to varying degrees. I tried to scrub off, thinking perhaps it was dead/weak, but it doesn't come off the rocks. See photos.

I had expected the algae to die off without any light.

Is this unusual for algae to survive so long without light?

Any advice for next steps? (I've been told to try hydrogen peroxide dosing, but I'm wondering if there are other things to try too.)

 

[Timfish]

Add some urchins. Dip the worst rocks in H2O2. Add corals and more fish and feed well. Be patient, it takes time to shift the equilibrium of a reef to promote corals over algae. See the below links:

Establishing a Healthy Microbiome in a New Aquarium Using Live Rock

Studying the effects of live rock in a newly established aquarium shows that high-quality live rock promotes the rapid establishment of an effective biological filter and a microbial community similar to those found in mature reef tanks.

www.reef2reef.com

"Coral Reefs in the Microbial Seas"


Changing Seas - Mysterious Microbes


Nitrogen cycling in hte coral holobiont


BActeria and Sponges


Maintenance of Coral Reef Health (refferences at the end)


Optical Feedback Loop in Colorful Coral Bleaching


Richard Ross What's up with phosphate"

 

[FingersCrossed]

Thanks. I've been hesitant to add more fish and corals because I thought it would be best to fight off the algae first. It sounds like your advice is that the algae may naturally lose out when the tank is stocked up. I'll also try the H2O2 and try some more turbos and urchins.

 

[Timfish]

Coral reefs are incredibly complex ecosystems and what's taken a long time to learn is corals are competing with algae for nutrients as well as manipulating the microbial processes. A common problem from what I've seen attempts to deal with algae by limiting nutrients may hurt corals more than the algae. You do need something to eat the algae and I would use urchins but if you want corals you need corals to promote the bacteria beneficial to them. Here's some videos by scientists I've collected over the years you may find informative:

"Coral Reefs in the Microbial Seas"


Changing Seas - Mysterious Microbes


Nitrogen cycling in hte coral holobiont


BActeria and Sponges


Maintenance of Coral Reef Health (refferences at the end)


Optical Feedback Loop in Colorful Coral Bleaching


Richard Ross What's up with phosphate"

 

[davidcalgary29]

Don't be afraid to add macro! After making sure it's pest-free, of course.

I've tried multiple different types, but have to give a gold star to halymenia. It's pretty, hardy, and easy to remove once it grows beyond an acceptable level. But many fish and inverts eat it enthusiastically, so it usually doesn't get out of hand. I find it to be a great nutrient soak and that may help deprive nuisance algae of its energy source.