Dinos or algae?

[reeferab]

Hi

I’ve got this nuisance algae (or maybe something else?) on a newish (established mid April 2026) tank that’s been getting steadily worse. It sort of sways in the waves and has strings of brown around it. There are lots of trapped bubbles in it as well.

Interesting whilst I’ve been away and feeding flake food via autofeeder in regular intervals and fixed amounts, it’s actually gotten better. Previously I was manually heavily feeding frozen at least twice a day.

I have a tuxedo urchin but it spends more time on the glass than the rocks.

I’m sorry I don’t have any meaningful parameters (nitrate, phosphate) to report beyond salinity is 1.025 and alk is 9.9 dkh. I haven’t done any water changes since the tank was setup.

Display volume is 120L.

Any help with id would be greatly appreciated.

 

[Kooma]

Honestly looks like both.

Hair algae covered in dinos.

 

[Mr. Mojo Rising]

I'm sure there is a few types of algae in all that. Not sure what is your strategy of never doing water changes and not testing, but personally I would start with a few large water changes and clean the glass and clean the equipment too, then start testing and keep the nutrients in check. Flake food from an auto feeder for extended period time puts a lot of nutrients in the water.

 

[jackintheboxfish]

Flake food and frozen food also have pretty different N and P ratios. Feeding one type of frozen food constantly might’ve skewed it and the flakes might’ve helped the balance. Thus “things looked better”.

Think the first thing you should do is get some test kits and get an understanding of your Phosphate and Nitrate numbers

 

[slingfox]

Take out the rocks and scrub them down. Do a large water change. This will make things look better.

 

[Gumbies R Us]

What does your CUC and filtration look like?
Parameters?

 

[MichaelReefer]

As a no water change person (didn't do a water change in nearly six years before my new tank...) I find if you're going to do it you really need to have an older stable tank with dosing and automated testing set up... When I started my last tank I had 2+ year old live rock that had been in my smaller tank, plus a ton of bio media.

In this case I would do a 50% water change, manual removal of as much as you can and then maybe do another in a few days.

 

[chris07958]

You've definitely got dinos mixed in there. Personally, I wouldn't do a water change until you've tested all your parameters. You need to know your current NO3 and PO4 before making a move. Manual removal is a good idea for a minute; you can try to siphon as much as possible through a low-micron felt filter sock or some filter floss and keep the water in the tank. Once you know your NO3 and PO4 levels, you can decide what to do. Take water to a store, or better still, send off an ICP test.