[DarkCobra]

Very nice photo!

That's staghorn, aptly named because it resembles antlers. A member of the red algae family, along with the more common black brush (BBA). If you're familiar with BBA, you're pretty much familiar with staghorn too. Generally controlled with the same environmental changes (less light, increased CO2/flow), and killed with the same treatments (H2O2 or Excel spot treatments, or Excel whole tank overdose).

And those are what I recommend you try first.

But know also that it also shares BBA's annoying tendency to sometimes laugh at what generally works. Mine was immune to the above treatments, and I had to invent a new treatment just to get it under control. Then it took another three months of experiments to find out why my previous attempts at environmental control were futile - in my tanks, instead of increased CO2 and flow getting rid of it, it only made it worse.

For now, assume that your staghorn responds normally though, as most does. Only fall back on my alternate methods if other means first fail you.

If you'd like to post some tank details (lighting, CO2, ferts, flow) we can look them over and look for obvious problems.

 

[DarkCobra]

No worries Raymond, it's worth checking into all possibilities. Since you're interested I'll provide my KH info as well. I use straight tapwater for 50% weekly water changes, KH is from sodium bicarbonate, and I've seen it vary from 8.0 to 9.5. It remains the same in CO2-enriched tanks. I've seen it as low as 5 in my tanks without CO2.

I'm curious what you consider exceptionally low. <1dKH?

Victor, if you have a KH test, please check it as well.

 

[DarkCobra]

The simple answer for any chemical treatment and shrimp is - no, not safe.

You can get away with it sometimes, especially with small H2O2 spot treatments of no more than 1mL per 10G of tank water volume. Less so with the other treatments of Excel, or H2O2/Excel combined. But safety is never guaranteed. Some shrimp are incredibly sensitive.

Removing the shrimp prior to treatment, then totally removing the chemical prior to reintroduction, is best. But that will typically require a large water change, and some shrimp are even intolerant to that.

In which case the only safe option for a chemical treatment is to remove the affected plants/hardscape and treat them "dip" style in a bucket, then rinse before replacing.

So extra emphasis on using chemicals only as a temporary measure here, to keep algae managed just long enough to identify what environmental changes will prevent regrowth. Trimming is an option too, but those Anubia 'nana' leaves are not damaged past salvage, and so I'd be loathe to snip them off on such a slow growing plant.

If you increase CO2 to see what happens, do so slowly, that's best for all livestock and not just shrimp. It's a current trend to try to hammer most algae problems into submission using CO2 alone, resulting in some ridiculous CO2 levels. Not necessary or livestock/biofilter friendly in my opinion. CO2 is only part of the equation, and if you find yourself pushing much past 30ppm, it's better to explore other options like light reduction.

 

[DarkCobra]

Currently no CO2 or liquid carbon, then? And also very low KH (carbonate hardness). Raymond might be on to something there. Some plants can utilize carbonates as a carbon source, though I'm not sure if anubias specifically can do so.

I'm not good at estimating light levels from LEDs, but it sounds like you have at least medium light. So some supplemental carbon source would be quite beneficial, or even necessary. If you actually have high light, then CO2 specifically would be necessary (no substitutes possible), or you'd need to lower light levels to medium. If you can get someone to provide a better lighting estimate it would be helpful to you.

Unless you have some reason you desire your current pH/KH, you could boost KH one degree by adding 1/4tsp. of baking soda; although I consider carbonates the least available carbon source (compared to CO2/Excel).