Green Diatoms or Something Else?

kittenbritches · Oct 7, 2021

I had the regular, young tank, tan-colored diatoms start growing on my sandbed a few weeks back. Last week I turned up my whites to check on things and all of my rocks are green.

I've tried googling the various algae types, read through the stickies, and sacrificed a chicken, but I can't seem to find an ID that fits.

The algae is neither slimy, nor stringy, but I did just find a couple of tufts of what I assume is GHA. The algae does not scrub off easily with a toothbrush.

I'm beefing up my CUC, and will be transferring everything to my new tank hopefully by Sunday or Monday. I did read a R2R thread from 2015 that said this type of algae is usually a precursor to coralline (which has been introduced to the tank via snails and frag plugs), but I don't want to get my hopes up, especially with the tank being so young. I would also rather NOT transfer green rocks to the new tank if it can be helped.

I did turn my white and red channels down on my lights when I discovered it.

Parameters
Temp: 78° F
SG: 1.024
pH: 8.0
KH: 9
NH3: 0ppm
NO3: 5ppm
PO4: 0.015ppm
Ca: 460ppm
Mg: 1160ppm (dosed after)

Current CUC
Handful each of...
• Margarita, cerith, nassarius, banded trochus, and astrea turbo snails
• Blue Dwarf and red tip hermit crabs
• An emerald crab
• A sand-sifting sea star
• A serpent sea star
• Scarlet skunk cleaner shrimp
• A red tuxedo urchin

Advise me! Is this all baby GHA? Should I be able to scrub it all off before plopping it in the new tank?

When I first noticed (whites only)

Just now (whites only with orange lens)

A tuft

Staghorn · Oct 7, 2021

What color chicken ? Is it like a green coloration in the rock? Not growing up off of the rock? The green coloration is like a phase (one of many) , if it’s puffy or hairy then could be gha. I would scrub anything you’re unsure of with hydrogen peroxide when you move the rocks

thewedge · Oct 7, 2021

Staghorn said:
What color chicken ? Is it like a green coloration in the rock? Not growing up off of the rock? The green coloration is like a phase (one of many) , if it’s puffy or hairy then could be gha. I would scrub anything you’re unsure of with hydrogen peroxide when you move the rocks

I agree. And I will just insert my standard plug for adding urchins to your system. I've had 2 in my 65gal for a few years and have not worried about algae at all, even during my lazy times.

kittenbritches · Oct 7, 2021

Staghorn said:
What color chicken ? Is it like a green coloration in the rock? Not growing up off of the rock? The green coloration is like a phase (one of many) , if it’s puffy or hairy then could be gha. I would scrub anything you’re unsure of with hydrogen peroxide when you move the rocks

Yeah, it definitely seems like coloration. I went at it with a toothbrush in quite a few spots and it wasn't coming off. Other than the couple of tufts I just found, you can't feel it on the rock. It's just there.

thewedge said:
I agree. And I will just insert my standard plug for adding urchins to your system. I've had 2 in my 65gal for a few years and have not worried about algae at all, even during my lazy times.

I *knew* I was missing someone on the CUC list! I've got one urchin in there now. He's spent the last two weeks on the same rock, with seven pieces of aragonite stuck to him.

thewedge · Oct 8, 2021

I didn't realize the green was more of a coloration of the rock rather than a field of turf algae. I can only speak for my tanks since I haven't really seen others, but all my rock looks green when I view it under just white.
I've resisted putting any rock from my 65g into my new Waterbox because I didn't want to introduce any nuisance algae. I figured it will get there on it's own. Plus I really didn't want to risk adding any of my invasive mushrooms to the new tank. But I spotted what looked like a completely clean rock in the back of the old tank and was going to add it on order to introduce some more bacterial diversity to my new tank. I took it out of the water and sure enough it too had a green tint even though it was shaded from the light. Back into the 65 it went.