What should I do?

Mike7744 · Aug 5, 2025

I have a 125 gal tank, (Fowler)
I had a real bad problem with green algae. For a long time and could not take it anymore. So I did a rip clean of the tank and set it back up. Bare bottom. 125 gal new water. I originally set this rock up with 4 pieces of ocean alive rock and 40 pounds rock about 3 years ago. This rock was in by 75 gallon. I transferred it over to my new build of the 125 gal.
Everything has been set up and running for a couple of weeks but now I am getting green algae on the formerly dry rock. ( omg can take it ) . So I took most of The Dry rock and put it in the sump. I cannot stand to look at it anymore. I don't.
Know why the dry rock is turning green again, but the live rock is not turning green.
I'm not sure what to do going forward. I'm afraid whatever rock I put in the tank will turn green and grow algae again.
now I have a small pile of rock in my display tank and nothing else. I'm in limbo right now. Not sure how to finish my tank and keep it algae free
125 gal tank
40 gal sump
curve 5 skimmer
Turf scrubber
4ft , t5 lighting

Ph - 8.2
Ammonia- 0
Nitrite- 0
Nitrate- 10
Alkalinity- 9.5
Phosphate- .25

Dom · Aug 5, 2025

Dry rock will develop algae unless you cycle it first. I made the same mistake once...

redfishbluefish · Aug 5, 2025

I'd consider API Algaefix. Note it is an algaecide and could kill inverts if you have any. Just make sure you follow directions. I'd also throw in a bubbler especially if you don't have a skimmer.

Garf · Aug 5, 2025

If you've got no coral, you can keep your lights really low. Otherwise algae will colonise bare rocks until they mature. R.I.P. cleans can just set you back on your quest. Snails and urchins help.

Reefering1 · Aug 5, 2025

Brown/ green, then red, pink, purple. At least your not dealing with dinos! Lower n/p and good husbandry will help slow algea growth while you get cuc up to par and time will do the rest..

Mike7744 · Aug 5, 2025

Reefering1 said:
Brown/ green, then red, pink, purple. At least your not dealing with dinos! Lower n/p and good husbandry will help slow algea growth while you get cuc up to par and time will do the rest..

I have a predator tank so a clean up crew is out of the question as far as I know.

Mike7744 · Aug 5, 2025

Dom said:
Dry rock will develop algae unless you cycle it first. I made the same mistake once...

This rock is 3 years old.

Reefering1 · Aug 5, 2025

Mike7744 said:
I have a predator tank so a clean up crew is out of the question as far as I know.

With coral?

Mike7744 · Aug 5, 2025

Reefering1 said:
With coral?

No coral, fowler

Uncle99 · Aug 5, 2025

There’s not a ton of surface area to develop your bacteria film. Few rocks, no sand.

And with predator tank, nutrients are more difficult to keep in trace and stable.

It’s the population of bacteria and algae which keeps rocks clean. The more surface area, the higher the populations grow.

For the most part, these populations are not seen (except maybe pods) but are the best CUC IMM.

I’ve not touched rocks or sand in years.

Trenton0115 · Aug 5, 2025

Mike7744 said:
I have a 125 gal tank, (Fowler)
I had a real bad problem with green algae. For a long time and could not take it anymore. So I did a rip clean of the tank and set it back up. Bare bottom. 125 gal new water. I originally set this rock up with 4 pieces of ocean alive rock and 40 pounds rock about 3 years ago. This rock was in by 75 gallon. I transferred it over to my new build of the 125 gal.
Everything has been set up and running for a couple of weeks but now I am getting green algae on the formerly dry rock. ( omg can take it ) . So I took most of The Dry rock and put it in the sump. I cannot stand to look at it anymore. I don't.
Know why the dry rock is turning green again, but the live rock is not turning green.
I'm not sure what to do going forward. I'm afraid whatever rock I put in the tank will turn green and grow algae again.
now I have a small pile of rock in my display tank and nothing else. I'm in limbo right now. Not sure how to finish my tank and keep it algae free
125 gal tank
40 gal sump
curve 5 skimmer
Turf scrubber
4ft , t5 lighting

Ph - 8.2
Ammonia- 0
Nitrite- 0
Nitrate- 10
Alkalinity- 9.5
Phosphate- .25

How many hours a day do you run your lights?

mpatterson42 · Aug 5, 2025

Can you just shut off your lights? Algae needs light to grow, so turn them off for two weeks, and any time it starts growing back turning them off again.

Mike7744 · Aug 5, 2025

Trenton0115 said:
How many hours a day do you run your lights?

12

vetteguy53081 · Aug 5, 2025

Mike7744 said:
I have a 125 gal tank, (Fowler)
I had a real bad problem with green algae. For a long time and could not take it anymore. So I did a rip clean of the tank and set it back up. Bare bottom. 125 gal new water. I originally set this rock up with 4 pieces of ocean alive rock and 40 pounds rock about 3 years ago. This rock was in by 75 gallon. I transferred it over to my new build of the 125 gal.
Everything has been set up and running for a couple of weeks but now I am getting green algae on the formerly dry rock. ( omg can take it ) . So I took most of The Dry rock and put it in the sump. I cannot stand to look at it anymore. I don't.
Know why the dry rock is turning green again, but the live rock is not turning green.
I'm not sure what to do going forward. I'm afraid whatever rock I put in the tank will turn green and grow algae again.
now I have a small pile of rock in my display tank and nothing else. I'm in limbo right now. Not sure how to finish my tank and keep it algae free
125 gal tank
40 gal sump
curve 5 skimmer
Turf scrubber
4ft , t5 lighting

Ph - 8.2
Ammonia- 0
Nitrite- 0
Nitrate- 10
Alkalinity- 9.5
Phosphate- .25

Can be from silicates and diatoms but from reflection, also see tank is near windows allowing UV rays to reach tank.
Add a few snails such as nassarius, astrea, turbo grazer and margaritas to help control

Dom · Aug 5, 2025

Mike7744 said:
This rock is 3 years old.

Doesn't matter.

Peter Houde · Aug 5, 2025

I've got nothing against skulls, but that is weird

littlefoxx · Aug 5, 2025

Mike7744 said:
I have a predator tank so a clean up crew is out of the question as far as I know.

What fish do you have? I also have a predatory tank and have had to get creative with clean up crews. Just need to know what fish you got before I can suggest anything.

Mike7744 · Aug 6, 2025

littlefoxx said:
What fish do you have? I also have a predatory tank and have had to get creative with clean up crews. Just need to know what fish you got before I can suggest anything.

Porcupine puffer, snowflake eel, spiny box puffer, lionfish. Foxface.