[KrangDog]

In response to some deterioating old growth, and continued water column PO4 levels of at or near 0ppm, I've been dosing 2ppm PO4 per day via KH2PO4. It's not going great so I'm at the end of that experiment.

But I've seen an increase in an issue that has been present to a small degree for a while. I've got some form of algae that seems to stick to new growth, gluing it together. It appears to be blue/green and goes wipe off. I've also seen an increase in a sheet like algae on the older leaves in a lot of plants. Again, it wipes off in a sheet. There's also a little bit of short thread algae hanging around, you'll see that in the photo below.

I've treated with Chemiclean to no effect, and more recently with PrecisionSolutions Cyano Solution, again with no effect. Some of these plants are carried over from a previous tank that was treated with Chemiclean in 2020 and responded well at that time.

Does this look like cyano to anyone else? Do I have some resistant, mutant strain? Lights are off at the moment so could only get a photo of the issue affecting new growth, but I'll get one of older growth once the lights come on and edit then.

 

[Plinkploop]

If it's cyano it's going to smell fishy when you wipe it off, if it's just sheet it will smell earthy. All the tanks I've dealt with cyano in have smelled pretty bad. It looks kind of like cyano, but sheet algae is so similar when there's that small of an amount that it's harder to say based on the picture and description.