Algae problem after new light

William Spak · Apr 22, 2025

Hello all!

I’ve attached some pictures below of an algae issue in my 75 gallon 7 year old reef tank.

This issue has happened ever since we got a new light- the blade coral grow. We had no algae before this light. The tank experienced a whole lot of coral growth with the new light followed by the growth of algae.

Water params are normal, phosphates are a tad high.

We have tried phosguard, chemclean powder, shutting the light off for 2 days, manual removal, but it keeps coming back.

Any suggestions?? Thank you!

Anna K · Apr 22, 2025

That looks like hair algae! I know people will chime in and ask you about your phosphate level. A few things that I've read that'll eat hair algae (besides you manually removing it) would be a sea hare, tuxedo urchins, and sometimes Turbo Snails. Fox face is a fish that's also been recommended a few times in threads I've read. Most people though will tell you to get in there scrub, filter, and pull until your happy.

Hopefully someone more knowledge will chime in for you!

Dragen Fiend · Apr 22, 2025

The change in light likely came with a higher par or stronger spectrum that hair algae likes. You can either dim the intensity or adjust your nutrient control. But if your corals are happy then ever. I would leave the intensity alone and focus on nutrients.

Whats your nitrate/phos at?

What sort of CUCs do you have?

I'd add a urchin and some turbo snails. They do tackle hair algae. Just nothing super long.

Freenow54 · Apr 22, 2025

William Spak said:
Hello all!

I’ve attached some pictures below of an algae issue in my 75 gallon 7 year old reef tank.

This issue has happened ever since we got a new light- the blade coral grow. We had no algae before this light. The tank experienced a whole lot of coral growth with the new light followed by the growth of algae.

Water params are normal, phosphates are a tad high.

We have tried phosguard, chemclean powder, shutting the light off for 2 days, manual removal, but it keeps coming back.

Any suggestions?? Thank you!

Can you change the light settings? Its not the light itself its the settings you are using I would think. Lower them to what you need

William Spak · Apr 22, 2025

Dragen Fiend said:
The change in light likely came with a higher par or stronger spectrum that hair algae likes. You can either dim the intensity or adjust your nutrient control. But if your corals are happy then ever. I would leave the intensity alone and focus on nutrients.

Whats your nitrate/phos at?

What sort of CUCs do you have?

I'd add a urchin and some turbo snails. They do tackle hair algae. Just nothing super long.

Parma’s are with normal range (I don’t have the values off hand). We have an urchin, and some snails. I do think we could use some more CUC

The thing is with the light, the corals began growing like crazy, but so did the hair algae. So perhaps we will try to dim it a little bit! I’ll update with what we change the settings to. Thanks!