green hair algae plague


New Member
Oh my word! My poor Nanocube12DX has green hair algae all over it for the past 5 months. The tank only takes about 2 days to grow 1-2" on EVERYTHING, including the gravel.
pH is stable at 8.3-8.4. Levels are low on all indicators: ammonia, nitrate, nitrite. calcium about 420-440.

So far, on the advice of the LFS and reefer friends:
For over a month. I did frequent water changes with LFS water. Changes with Ocean Salt water. (1 gallon, 2X a week)
For over a month I watched the levels and did no or minimal water changes (1 gallon every 3-4 weeks)
For a few weeks, I took our and scrubbed the live rock every day or two, rinsed it with salt water, and put it back in the tank.
Bought 5 snails to graze the rock. Bought a few hermit crabs. Even bought a tang to graze the tank - the fish died (I think the tank's too small!) and killed stuff in the live rock (died over the weekend. oh oh, when I got in to the office that Monday morning!)
About 2 months ago, I lowered the light level to 5 hours a day (currently running 48wts; the light output can be upped to 96. Is a retrofit. I bought so I could grow high light corals.)
Took the bio-balls out of the back on someone's advice.
Added a protein nano-skimmer on someone else's.
Except for scrubbing the algae off every few days to keep it off the 4 corals that are left (outside of the tank of course), I've left it alone for about 4 weeks to see THAT will help. Nada. My poor xenia, which used to pulse in fine fashion, is hardly moving with all the overgrowing.

I've tried everything my LFS has suggested... they've said there's a root cause. We haven't been able to find out what that is.

Please - does SOMEONE know what I can do? Anyone dealt with this? I am almost ready to pitch the rock and gravel to start over! Thanks!!! for your help


New Member
hmmm - i'll have to look back at your tank and its stats then i'll get back to you
in general algae =
1) high NO3 but your water changes should have fixed that unless your source water is bad
2) high PO4 same as above but a phosphate remover like GFO may be in order
3) bad bulbs - bulbs that are old or of the wrong spectrum tend to grow algae very well
4) too high a bioload ie to many fish/inverts not enough corals in tank/macroalgae in a fuge
5) lack of mech filtering like a sponge or filter floss that is cleaned daily
6) improperly cured live rock
this is very general but obviously your system has shifted to a hair algae driven system vs a bacterial coral photosynthesis system. check each of the things i mentioned and hopefully you'll find your root

The Kapenta Kid

New Member
May I join in?
I have a 15 gal that has been set up for about 6 months. I have never been able to rid it of hair algae. Fishload is low, a couple of small gobies, 10-15% water change weekly, turbos and other snails and hermits for clean-up, 96W T5 lighting, water params 0,05 phosphate and persistent 25 ppm nitrate. I use RO/DI salt water.
I had hoped to add corals long ago, but it doesn't seem possible in these conditions.


New Member
kapenta - i would say your prob is #6 above. curing live rock properly - in the dark for a month or more with just a pump for circ while you occasionally brush, swish, and change water - maybe the most important thing you can do for a new system.
and here is another one noone else will tell you - after you have cured your rock properly - it goes CORALS FIRST then fish. i have told people this many times on this board but every time people think they have to add fish and then eventially put a couple corals in - that is completly backwards. although this applies to all reef tanks with nanos it is even more important. you should have a thriving ecosystem before you add your low bioload of fish. this way bacteria and coral/coralline algae photosynthesis can out compete algae


New Member
after you have cured your rock properly - it goes CORALS FIRST then fish.
This is very interesting. I've heard it before at my LFS, but didn't believe it. Now I'm beggining to though. This type of information needs to be a "sticky" in the begginer forum, don't you think?


New Member
I had a great functioning nanotank for a few months. Got the cured live rock and sand with the tank, but left it for 6 weeks "just in case. Then added some corals, after a few more weeks I added 3 fish (2 percs and a spotted goby), everything was fine. I had an arrow crab that kept everything clean, a few hermits and snails. When the crab grew, I swapped him for a peppermint shrimp, and after that everything started to go haywire.

I'm tempted to just to start over! But I'm keeping on trying to balance the tank - the corals seems to be doing ok as long as I keep pulling the masses of hair algae off them. If I had a coral-minder, I'd hand them over for safekeeping and start over. I just don't want to kill off what's alive! have 1 leather, 1 gold gorgonia, 1 small pulsing xenia and 1 hard coral (acroporia?) I'm not impatient - wouldn't mind going through a 3 month start-up cycle again to get it back to balance. But don't want to kill the corals!

I didn't get whether the algae would be less or more with some fish? The original fish and lots of stuff from the live rock died when the pump clogged (algae plugged it while I was away for the weekend). Haven't had fish in the tank since April; bought some snails and hermit crabs, but they're not doing anything for the algae OR keeping the tank clean. I haven't fed it for 2 months hoping that would help.


New Member
the massive die-off and lack of flow is likely the cause of your troubles. it shifted the balance out, adding tons of organics and killing off much of the rocks benificial bacteria due to lack of O2 - shifting it to an algae driven system. you could theoretically continue what your doing and eventially pulling massive amounts of HA out of your tank will reduce the nutrients and bring it back

here is what i would do if i had your tank
1) remove all the rock and water and do the two bucket curing method that i often recommend on this site. use some of the water to do an initial scrubbing and the rest can be your first week curing water. you will need to scrub and move the rock to new water each weekend. all you need is a pump as ambient room temp will be good enough.
2) fill the tank with 100% new water and leave just the corals and and CUC you have in the tank on eggcrate or bare bottom with as little rock as possible ie just what the corals are attached to.
3) after the rock has been cured properly add it back to the tank with a new bag of sand
4) after getting up and running again - make sure you keep your mech filters clean and vacuum part of the sand during each water change. you can add a couple fish at this time. fish produce waste that feed the bacteria and corals in a balanced system not the algae - see the difference?
if this doesn't work then maybe your LFS source water isn't what it should be


New Member

That's what I'll do. I'll start the 2 bucket system this week and let you know how it goes in 4-6 weeks... thanks so much! The nano is absolutely sustaining algae and needs intervention and a kick-start back to reef maintenance.


New Member
If I may.

Further strategies to help control nuisance algae.

After cleaning your rock you might want to increase your tanks water movement to at least 10 times your tank volume per hour to help export excess nutrient to your filtration system.

Use only quality salt like Tropic Marin Pro or Reef Crystals (my brand of salt) on RO water preferably. Just select one type and consistently use it.

Do you have a refugium? if you don't, I feel you should consider one and try to grow some chaetomorpha algae, also known as spaghetti algae to compete directly with these nuisance algae. This will help control and may even solve your problem. Sadly, the new cleaned rock (or even no rock at all) can/will develop the same algae/problem from spores left about, if you continue to have the same prevailing conditions. It best to make sure you create competition for nutrient.

What exactly is your lighting? 10,000K, 50-50 combo, 6500K etc. If you have actinic(s), I would run ONLY actinic lamps for an 8 hour photoperiod for now. After your problem is under control, I would slowly (over the course of 1 to 2 weeks) increase the light back toward "normal". The life on the rock needs light, however it can get by on small amounts right now, which is being smothered by hair algae anyway.

If this was my tank. I would not add any fish yet. Only corals for 2 to 6 months up to the time I have favorable coralline growth.

Between water changes, pay careful attention to pH and alkalinity. Try to maintain consistent and proper water parameters to favor coralline and inhibit the nuisance algae.

Mine is as follows:

SG: 1.026
Temp: consistent 80F winter (even when changing water). Fluctuates 80F to 81.3F (summer)

pH: 8.3 - 8.4 (high range)
Ca: 420 ppm
Alkalinity: 3.4 to 4.1 meg/L
Mg: 1350 ppm

Ammonia and Nitrite: 0
Nitrate: less than 10 ppm
PO4: less than 0.03

Lastly, try to increase biological controls like snails (not fish...LOL). The snails btw is not there to eat the hair algae (LOL) but to make sure it takes care of the uneaten food, detritus, etc. which often lead guess right...excess nutrient. May I suggest a combination of Nerite and Cerith snails.

Given water, light, some nutrient base, algae are going to invade and proliferate in your system. The focus here will be on preventing and controlling undesirable forms. This btw is not terribly uncommon for a new tank and will be replaced in time with "higher level" algaes (Coralline) provided you maintain good water quality.

My personal take is this: Micro- and macro-algae growth is an indication of a normal, healthy state. It is just that our hobby lacks the check and balance of a real reef environment. If a hobbyist "fails" in maintaining excess nutrients (PO4 <0.03ppm, Nitrate <10ppm, Dissolved Organic Carbon compounds, etc) to manageable levels then expect algae bloom.


New Member
Just a quick question... If we pay for live rock.... why kill whats in it by "cooking it", doesnt that defeat the point?


New Member
All my water parameters are the same as yours. Same pH, same calcium, etc. This is what's been so frustrating. However, it was an old post, and meanwhile, I have had two little fishes in for 3 months - they are thriving, along with some hermit crabs, some corals added after summer - everything's doing great. I'm resigned to the algae and rip it off with tweezers and scrub it and rinse off the rock in a separate bowl with salt water when it grows back. ugly, but seems to be working and I love my tank :) I use the same water for changes (Ocean).

I'll try your suggestions and see what happens. The buckets did nada. oh well. Thanks everyone...


New Member
Light: I run for 4 hours on 2 hours (noon) off, 3 hours on - for the past 3 months. 96watts (upgraded lighting, which I run at 2 bulbs - 48 wts- on for an hour or two, then 4 bulbs on over a few hours around noon, then back to 2 bulbs before end of day). I tried less light for a month (4 hours a day) and it seemed to make no difference, so I decided to give more light for the corals.

I don't have room for a refugium, unfortunately. The deluxe Nano12 is on my desktop at work. I only feed days when I'm working, rest the tank on the weekend.


New Member
Did anyone else notice the word GRAVEL being used in the OP?
Is the substrate "gravel" or crushed coral or sand??? Very important determination.
Gravel and crushed coral would become nitrate factories.

Ritsuko N

New Member
Rosemarie, that without a doubt is one of the worst algae horror stories I have herd to date. Sounds like you did a lot of the right things as far as corrective action goes, not sure why it didnt work out better for you unless the algae was misidentified Bryopsis.

That was a great post from johnanddawn as most algae issues can be traced right back to these notorious six factors. Another great post by glory17. A lot of good info in those 2-3 post. I too favor making the first additions to my tank, corals once its been properly cycled with cured rock. It makes for a very minimal impact and bio-load on a tank allowing for a slower more gradual build up in bio-load as opposed to immediately adding fish, especially in smaller systems such as Nano's. Of course thats just my humble opinion.

Yes I too picked up on the "gravel" part. Potentially this can have a major impact on the chronic algae issue. Im not thrilled about spending the money on substrate that I do anymore than anyone else is, but there are several reasons for doing so or at least using calcium based substrates. There are some cheap alternatives to paying 23.00 for a 20 lb bags of Carib-Sea.

Cooking your rock shouldnt render it non-live rock if done properly. In fact this is a great way to use "used live rock" thats being sold off for pennys on the dollar by someone getting out of the hobby as most people are getting out of the hobby is a result from the flustration with being over ran by pest algae and not being able to control it. Cooking rock will eliminate most pest algae although its only moderately effective with Bryopsis while still allowing one to maintain the bacteria cultures contained within the rock.

Hopefully rosemarie you can get the upper hand on this issue and spend more time enjoying your tank instead of fighting it.