Freshwater Coralline Algae Growth??

It spread very quickly, I replaced this tube but I now see it starting in other areas BEFORE the UV. I am starting to think it is just some advanced/mature version of brown algae. The weird part is if you look inside the tube it is brown not red, the inside is not red at all!



I also see spots with this black stuff I assume is just another strain of algae?

Just an update on this bizarre situation, the tube has now dried out and the algae is crumbling off the tube. To my surprise the red color is the tube itself and not the algae...the algae has separated leaving a stained pink tube. Chemical reaction with the tubing material maybe?

It strikes back! You can clearly see the purple algae on the bottom and the green on the top...so bizarre but I am sure it can't be harmful, if anything helpful?

I let it go for a while just to see what happens, it looks more brown than red in person and seems to have really appeared when I introduced the ADA Amazonia. Nerite snails seem to have no problem munching on it thankfully.

As far as the strength goes, it sticks harder than the green algae pictured...about as stubborn to remove as the lime green dot/spot algae. I can not use a blade to remove it vertically because of my curved bow front.

It could possibly be two different problems in one package - an algae forming over a biofilm containing Serratia marcescens (the pink bacteria that grows on damp/wet surfaces in bathrooms and food containers). If it is S. marscescens in the tubes, it would be gram negative, so wiping it out without murdering your nitrogen-oxidizing bacteria might be tough. Plus, it may come back if conditions are right (it's an airborne bacteria). It likes phosphates, fats and stagnant water when growing in bathrooms, and doesn't care about light (I don't know if it likes those conditions in a tank, but you may want to check your phosphates, if you already have the tests). It acts as an opportunistic pathogen for people and other mammals, though it can only infect us if we have a VERY weakened immune system. It may infect your fish if they are already sickly, since I'm seeing a few studies that pop up naming it as a fish pathogen, too.

Not sure if that's what it is though, but giving you another possibility. Don't freak out and nuke your tank, I'm pretty new to aquaculture, so hopefully an old-timer will chime in and say that it can't be that stuff, or isn't dangerous in an aquarium setting.