New to Reef Tanks - Green Hair Algae and Red Slime Algae


Reefing newb
Hi, I'm new to Saltwater Reef Tank owning and I have a massive issue with green hair algae and an occasional issue with red slime algae in my tank. It is all over my live rock and back wall. Every time I do a water change (once a week) I take a toothbrush and scrub it off the rock and try to siphon as much of it out as I can. However it doesn't seem to go away.

I have a 29 gallon nano tank with 2 mexican turbo snails, 5 nassarius snails, and a handful of cerinth snails. I also have a diamond goby, a 6 line wrass, a purple fire fish, and a royal gama. I have a few, maybe 3 left, blue legged hermit crabs and a peppermint cleaner shrimp. I also have an orange sea cucumber.

I have an MP10 to help with water circulation and a protein skimmer. I also have a UV light filter to help kill algae in the water.

What else can I do to help get rid of this algae? Is there any other creature I could add to the tank to help eliminate it?

One of the sites I order fish from has a sale on 50 Snail Cleanup Crew (20 Nassarius, 20 Cerith, 5 Nerite, and 5 turbo). Would this overload my tank since it is only 29 gallons?

Desperately in need of help. Thanks.

Your best bet is to get to the root of the problem (find out what's causing your algae) instead of adding more animals to eat it.

What are your water parameters? What kind of water do you use (tap or RODI)? How big are your water changes?

How much and how often and what type of food do you feed?
I am currently using RODI water that is premixed at my LFS. I change out about 5 gallons each time I do a water change.

I am feeding about half a cube of frozen Mysis shrimp that I defrost overnight and then wash in RODI water.

I am embarrassed to say that I'm not sure what the parameters are. I have not tested the tank for a bit. My husband set up some sensors for pH, temp, and OPR. None of the alarms have gone off on it.

I have filter cloth, chemical elite, and purigen filters in the back.
After reading up on a few other articles. I believe what I have may be Bryopsis and not hair algae, or possibly a combination of the two. I have what looks like little ferns on some parts of the rocks.
Welcome to the does sound like bryopsis if it has fern like branches. If so, a good method to get rid of it is to dose your tank with Kent m magnesium. Good luck.
Welcome to the algae can be a pain. Are you running a refugium? Normally if you have hair algae or for that matter any kind of algae you have phosphates in the water. How often are you feeding? How old is the live rock? is it true rock from the ocean? There could be countless causes..How old are your bulbs? How long are they on? How much water turn over do you have in the tank? Answer all that and anything else that you can think of and we will help get to the root cause...
Thanks for all the responses. I have not tried magnesium but I will look into it.

I am not running a refugium though it is on my list of things to add to the tank. I feed once a day, half a cube of frozen mysis shrimp. The live rock was purchased from my LFS about 6 months ago. I'm not sure how long they had it. I doubt it is from the ocean because they make their own live rock in a tank in the back. The bulbs are also about 6 months old. I keep them on for about 7 hours, 7 am to 2 pm. I'm not sure what you mean by water turn over. Sorry, I'm really new to this and still trying to figure it all out.

I want to add corals to the tank but I don't want to do that until I get rid of the algae. I would hate to kill any creatures with ignorance.

Thanks again for the help.
A refugium would help a lot. Might want to cut back on the feeding...seems like a lot. Fish are swimming pigs and will want food anytime they see you but every other day or every third day should be fine. More then likely that is where your phosphate is coming from. If it was me....I would do a total black out for 5 days. No lights, even cover the glass with paper, blanket, whatever...I mean not feed the tank at all..Then after do a big water change and start feeding every third day...Tank turn over is how many times the water is pumped in a hour. Take the total gph of all water flow devices and divide by the tank volume. Fowlrs are 25 to 35 times per hour Reefs 40 to 50
Not feeding the fish for 5 days won't kill them?

When I feed every third day, do I still do only half a cube?

Thanks for the advice.
This fish will be fine without food for a few days if you feed them before the blackout

I would also like to add that I would not defrost the food overnight, that's a long time, and bacteria could easily start to spoil the food by then. I thaw my frozen for about 20 minutes in a small container of tank water and its usually thawed enough to feed
If you do dose with magnesium, I'd pick up a test kit and test your levels first and then raise it slowly. Also a good idea to test your nitrates and phosphates. What do you have right now for a clean up crew? Check out to get a sense of how many snails you need for a 29g - I'm not sure off the top of my head, but their packages are pretty accurate! As for the red slime (cyano), what do you have for flow in your tank (number of powerheads and gallons per hour for each)?
No the fish will be fine going a few days with no food or light. I agree on the thaw time as well. The reason I asked about the tank turn over was about the cyno as well. Cyno does not like higher flow in the tank. That is one of the main reasons for such high turn over rates. Which salt are you using?
I thaw the shrimp overnight in the fridge. This is bad for bacteria? How would I keep the other half of the cube good? Cut it in half frozen and then thaw each half individually?

For flow, we have 2 powerheads (not sure how much water they move since they came with the tank, its a nanocube) and an MP10.

The salt is premixed at my LFS so I'm not sure what type they are using.

I just checked with and they have a lot more snails in their cleanup crew than we currently have. I made the mistake of getting a bunch of hermit crabs. I added extra shells for them but my Goby kept stealing them and stashing them under rocks. This caused my hermit crabs to start a minor snail-a-cide. I'm down to only about 3 hermit crabs now and one green crab. I'll see about upping my snail population after I try the blackout.
Yup I cut a cube of frozen then put it back in the tray for next time. more snails would be a good thing after the black out. Hair algae is a real pain but thats how i took care of it when I had it.
I know how you feel believe me.
I had an outbreak of green Hair Algae, along with red slime. I used Phosban and it went away. Two months ago it came back. I used more Phosban and it's not working. Now I have a dwarf Tomato Clown that has taken up with a clump of hair algae like it's an anemone, spreading the algae spores around. Unless I can catch the TC and take it back to the store, I won't be able to control the GHA.

Now, for the Red Slime Algae. When I'm doing my weekly water change. I use a piece of air hose and suck the RSA off of the rocks. It's a pain in the butt, but it works for 4-5 days.
When I've had hair algae or over growth of any kind of green algae in the past it has been corrected by elevating my PH to 8.3. PH tends to drop in most reef systems especially if you live in an area with acidic water. Check PH and correct it by using buffer - not reef builder. Reef builder by itself is good for increasing PH stability or KH but won't correct PH.