That Weird Algae Is Back

[Kaidonni]

So, I was taking a look at the tank today, and that weird algae I posted about at the start of August has returned (found here). This time it isn't growing on the roots of baby java fern...at least, not when I last looked, but I'm removing the baby java fern sprouting on the big plants each week anyway after what happened before. I made a quick video of it, and got some good focus on it (far better than any photo I can get). I tore that bit of the leaf off just to be safe...
 
I did test the water parameters last weekend
 
- ~0ppm ammonia (as best as I can tell with Nutrafin and API test kits, it's the same as it's always looked for ages now)
- 0ppm nitrite
- 20-30ppm nitrate
- ~7.5pH
- ~370ppm Total Dissolved Solids after the weekly 50% water change on Sunday - was ~490ppm beforehand (the remnants of aquarium salts I dosed at the beginning of August)
- Tank lighting is Sun-Glo 46cm 15w T8, on for 6 hours a day from 2pm to 8pm. I do not dose with any fertilisers at present.

 

[Ch4rlie]

Having had a look at that video, it looks like a form of Black Brush Algae (BBA) to me, though does resemble Staghorn algae as well, sort of.
 
Have a look at this link, I do find it useful personally as a guide, and the middle image under Black Brush Algae, BBA seems to resemble best what was shown on your video.
 
James Planted Tank - Algae Guide

 

[Kaidonni]

Thank you for the reply. To be entirely honest, I relate the colour and how it had been growing on the roots of the baby java fern back at the beginning of August to the one picture of blue green algae in that link (the leftmost one). It had a similar consistency, webbing across the various roots of the baby java fern, a bit like a sheet. The colour of the bit I filmed and removed today is also strikingly similar. I do remember removing another piece of thread-like algae of the very same colour from this plant a few weeks ago or so (or at least spotting it - I think I tried removing it with a pipette, and then lost it, or just plain forgot about it being on the plant).
 
Just in case we're looking at different things, I've been looking at the algae on the tip of the plant, swaying in the current - with a little along the upper edge, just down from the tip, also swaying in the current - which is blue-green looking to me.

 

[Munroco]

Blue green is what I was thinking. Does it rub off the plants easily? Blue green algae appears more as a film than individual strands like BBA, and when you pick it off its like a slime.

 

[Kaidonni]

No idea, I never tried rubbing it off, just breaking the tip of the plant away (and uprooting it at the same time...). The same with the baby java fern, I just tried my best separating them from the main plant, never tried rubbing any of the algae off.

 

[Kaidonni]

Just a little update - I rubbed some algae off my vallisneria this afternoon when I noticed it while the tank light was on, it appeared thread-like but it didn't look as blue-green as the other algae (but that could just be due to it being closer to the surface of the water/the effects of the tank lighting on my perception of the colour). There were a few single strands of thread here and there. It may also have been just general "hair, thread, fuzz" as listed in the link provided by Ch4rlie (some of those pics show algae that looks blue-green, so maybe it's what I was looking at yesterday? Or maybe not, maybe it was blue-green algae yesterday at the least, and maybe it also was today).

 

[Wildbetta]

It might be BBA which can come in some different colors(green, black, rust red ect).  However to me it looks like a type of filamentous algae -- shown under that link from Ch4 as Hair, Thread, Fuzz, ect.   Might actually be a bit of a couple of different algae -- BBA, the hair, fuzz, ect, and green spot.   It in no way resembles blue green algae (cyno) to me.