Opae Ula tank with normal marrimos: after 2 years, something new has sprouted?

[Ndrewtan]

Hi all, about 2 years ago I moved my shrimps to new tank and I experimented with Marrimo Moss balls.

You can view my past videos here if you're interested. There are 10 videos updating the status of the tank and the moss balls.

https://youtube.com/playlist?list=PLQdr ... gBon0IKMtX

Now after about 2 years recently the moss balls have started browning and seem to be dying off. That's not that much of a surprise, but what was a surprise was that I have one particular moss ball, sprout a very aggressive and long algae tendril out.

https://youtu.be/5-76_Z0OlnE

I'm pretty sure it is not hair algae, but I have no idea what it is, if it is the moss ball itself growing, or it was something else embedded in the mossball. The sprout appeared nearly overnight. In fact, this was the second sprout. The first one was even longer (>10cm) on another mossball, but it disappeared after I went overseas for a holiday and did not leave the aquarium enough sunlight.

My tank parameters
Salinity : 1.007sg
PH: 6.7
No filter, only top up with bottled RO water.
I feed the shrimps whenever I like. Usually once a week to once a month. Usually one or two tiny shrimp pellets. Sometimes spirullina powder.

Shrimp are still berrying and larvae developing so I guess everything is good.

Hoping I can get some help identifying what is this algae. Also, for those who want to try marrimos, mine lasted for 2 years. Not sure if they are dying now because of the brackish water, or something else caused the die off. They didn't really grow too.

[Vorteil]

Same form of chaeto sold here. Part of it just happens to have thicker strands that seems to grow that way sometimes. I have the same thing. Seems your SG is on the low side. These are the best pics.

[Ndrewtan]

Is it normal for Chaeto to suddenly sprout in a tank that never had Chaeto, after 2 years? Only water Input is bottled RO water.

[Harry]

I had chaeto pop up from nowhere! There may have been some tiny pieces when I bought my shrimp ten years ago. Or perhaps it forms from spores in the air/ But I do know that algae is a natural phenomenon.