Turf algae and Cyano? How to resolve long term?

Radon · Feb 10, 2026

Recently came back from vacation after already battling turf/gha problems. Now it is extreme.
I've tried many different algae eating invertebrates to no avail. Tank was previously having perimeter swings, but has been steady. Clowns are hosting the algae at this point so manual removal=chewed up arms and holes in gloves. I need to get a microsope to see exactly what I’ve been battling. I think I’ve lost a lot of my clean up crew. Any advice is much appreciated. I’m hesitant to use reef flux, because something else may pop up (Dino’s or more cyano). I have a refugium, but chaeto is being out competed by gha. I’ve never had much coralline algae.

Perimeters: 78F
1.025 salinity
Nitrate 5.6
Phosphate 0.2
Magnesium 1645
Calcium 446
Alkalinity 8.9

zwalter38 · Feb 10, 2026

IMO its is kind of crazy that you have any nitrates or phosphates with that amount of turf algae, so there must be some underlying issue causing a buildup of nitrates. If it were me i would manual remove to start. I know you said it isn't really a choice but i would think it sort of has to be unless you go a chemical route which i personally wouldn't recommend. Maybe try removing the clowns while you clean? So here is how i would personally tackle it

1. manual remove as mush as humanly possible. I have used an old canister filter to help me vacuum as I go.
1a. Water Changes will help remove algae and excess nitrates and phosphates.

2. boost your standard cleanup crew with hermits, some trochus or astrea snails, maybe an urchin if you'd like, and maybe one or two turbo snails. looks like your tank isn't too big based on the pictures so one or two turbos should be good. this cleanup crew would be here to stay.

3. if your local lfs or a friend would be willing to loan you a sea hare they are monsters at eradicating GHA. However they will starve quick so you would have to have a plan to return or rehome it.

4. if your chaeto is overrun with GHA id possibly consider starting with some fresh stuff if you thinks its beyond recovering.

5. IMO like I said I believe you have way more nutrients in the system then what your tests say. The turf algae is consuming loads of it at that size. so where is it coming from....Overfeeding? Not enough nutrient export (skimmer, chaeto, water changes), Overstocked?

just my 2 cents as I also battled and overcame turf algae without chemicals.

Radon · Feb 10, 2026

zwalter38 said:
IMO its is kind of crazy that you have any nitrates or phosphates with that amount of turf algae, so there must be some underlying issue causing a buildup of nitrates. If it were me i would manual remove to start. I know you said it isn't really a choice but i would think it sort of has to be unless you go a chemical route which i personally wouldn't recommend. Maybe try removing the clowns while you clean? So here is how i would personally tackle it

1. manual remove as mush as humanly possible. I have used an old canister filter to help me vacuum as I go.
1a. Water Changes will help remove algae and excess nitrates and phosphates.

2. boost your standard cleanup crew with hermits, some trochus or astrea snails, maybe an urchin if you'd like, and maybe one or two turbo snails. looks like your tank isn't too big based on the pictures so one or two turbos should be good. this cleanup crew would be here to stay.

3. if your local lfs or a friend would be willing to loan you a sea hare they are monsters at eradicating GHA. However they will starve quick so you would have to have a plan to return or rehome it.

4. if your chaeto is overrun with GHA id possibly consider starting with some fresh stuff if you thinks its beyond recovering.

5. IMO like I said I believe you have way more nutrients in the system then what your tests say. The turf algae is consuming loads of it at that size. so where is it coming from....Overfeeding? Not enough nutrient export (skimmer, chaeto, water changes), Overstocked?

just my 2 cents as I also battled and overcame turf algae without chemicals.

Should I just manually remove as much as I can? I was thinking about taking apart my rockwork and using a diluted hydrogen peroxide solution in a seperate container. My concern with that would be impacting the bacteria in the rocks. I don't have many corals atm. I believe over feeding was the cause while my brother was pet sitting. The tank isn't overstocked, previously my nutrients were bottoming out and I had cyano problems. Long story short I've been dealing with different breakouts after a long fallow period due to ich. Thanks for the advice.

zwalter38 · Feb 10, 2026

If it were me I would just manually remove as much as I could. if its simple to remove the rocks I would just scrub them in a separate bucket of saltwater with a tooth brush or something. i don't think that would damage the bacteria that much however you could always add back bottled BB if you were concerned. I'm unsure about the hydrogen peroxide effects on the BB but I don't believe it is necessary to take the risk.

Radon · Feb 10, 2026

My sump consists of filter sock for mechanical filtration, ceramic media, sicce protein skimmer, refugium (freshwater led plant light, and red/purple cheap grow flood light led). Should I look into a single high quality fuge light? It does grow algae well currently. I may look into increasing the flow for chaeto.

Subsea · Feb 10, 2026

Your measured inorganic nutrients are good. I would get nitrate higher. Anywhere from 5-50ppm. Phosphate is a bit high. The other measured parameters are spot on.

For long term algae control: competitors and consumers should be the focus. I focus on micro fauna & fana to establish multiple nutrient pathways and use diver collected live rock & live sand to accomplish that.

Because you are losing CUC, I suspect some Dinoflagellets to be mixed in with the GHA.

Radon said:
Should I just manually remove as much as I can? I was thinking about taking apart my rockwork and using a diluted hydrogen peroxide solution in a seperate container. My concern with that would be impacting the bacteria in the rocks. I don't have many corals atm. I believe over feeding was the cause while my brother was pet sitting. The tank isn't overstocked, previously my nutrients were bottoming out and I had cyano problems. Long story short I've been dealing with different breakouts after a long fallow period due to ich. Thanks for the advice.

Manually remove as much algae as possible from rocks & substrate. Then I would dismantle rock work and soak each rock for a 10 minutes in a 10% solution of 3% peroxide. Scrub with brush and remove algae and flush off with tap water and return to tank. One week later I would RIP clean your substrate with tap water in 5G bucket until it runs clean. Return substrate to tank. The fresh water rinse WILL NOT remove all good bacteria plus you have established bacteria in your rock and on every flat surface in your system.